worktoolprotruding forward froma frontside with respect to the body case; a motor to drive the work tool; and a battery to supply electric power to the motor. The motor is accommodated in the body case. A top handle is ex- tended in a longitudinaldirection atan upside withrespect to the body case and a side handle is provided at one of a right side surface and a left side surface of the body case.The batteryisdetachably mounted in a batterypart formed behind the top handle. An interference reduction part is formed behind the top handle to reduce interfer- ence with a palm holding the top handle or a wrist. The interference reduction part is formed by the batt mounted in the battery part so as to have an upper end part thereof positioned at a side closer to the one of the right side and the left side with respect to a rear end part thereof. 

[0011] When the operator holds the electric power work device of the present invention, the operator holds the side handle with one of the right hand and the left hand, and holds the top handle with the other hand. The electric power work device according to the present in- vention includes the battery part and the battery shifted to a side closer to the one of the right side and the left side. Accordingly, the palm or wrist of the other hand of the operator can be moved to the one side. Therefore, the electric power work device of the present invention reducesinterference withthepalmholding the top handle or the wrist during operation, and a degree of freedom of a hand movementincreases.As a result, the handling of the electric power work device and working efficiency are improved. 

[0012] Certain exemplary embodiments will now be described in greater detail by way of example only and with reference to the accompanying drawings in which: 

FIG. 1 is a side view of a chain saw according to a first embodiment of the present invention; FIG. 2 is a plan view of the chain saw according to the first embodiment of the present invention; FIG. 3 is a perspective view of the chain saw, with a battery removed, according to the first embodiment of the present invention; FIG.4 isa perspective view ofthe chain saw accord- ing to the first embodiment of the present invention, as viewed from the front upper right; FIG. 5 is a plan view of a chain saw according to a second embodiment of the present invention; and FIG. 6 is a rear view of a chain saw according to a third embodiment of the present invention. 

[0013] A description will be given of examples of em- bodiments ofthe presentinvention indetailappropriately with reference to the drawings. 

[0014] In the description of each embodiment, same components willbe denoted bythe same reference symbols, and overlapping descriptions will be omitted. 

[0015] In each embodiment, a configuration, in which the present invention is applied to a chain saw to cut a 

tree,a plate, or the like,willbe described as an example. 

In the following description, a cutting part of the chain saw is on the front side, and a top handle thereof is on the upper side. 

5 

## [First embodiment] 

[0016] As shown in FIG. 1, a chain saw 1A of the first embodiment includes a body case 10, a cutting part 20 set to the body case 10, a motor 30 to drive the cutting part20,anda battery 90. The cutting part 20ofthechain saw 1A is driven when the battery 90 mounted in the body case 10 supplies electric power to the motor 30. [0017] As shown in FIG. 3, the body case 10 includes a body part 11 which is a resin box, and a top handle 40 arranged on the upper side of the body part 11. Thus, the top handle 40 is arranged on an upper part of the body case10.Further,the bodycase 10 includes,on the left side surface, a side handle 50. 

10 

15 

[0018] Note that, in the first embodiment, the left side of the chain saw 1A indicates one of the right side and the left side in the appended claims, and the right side of the chain saw 1A indicates the other of the right side and the left side in the appended claims. 

20 

[0019] As shown in FIG. 1, the motor 30 is accommo- dated in a front part of the body part 11. The motor 30 is a popular electric motor. An output shaft 31 of the motor 30 extends in the lateral direction. 

25 

[0020] In addition to the motor 30, a control board (not shown) to control the driving of the motor 30 and a drive mechanism such as a driving gear (not shown) coupled to the outputshaft31 ofthe motor30 areaccommodated in the front part of the body part 11. 

30 

[0021] The top handle 40 is arranged to continue to the upper surface of the body part 11 and extends in the longitudinal direction above the body part 11. 

35 

[0022] The top handle 40 includes a front end part 41 protruding upward from a front end part of the uppersur- face of the body part 11. The top handle 40 includes a rearend part42 coupled to an upperend partofaholding part 13 of the battery part 12 described below. 

40 

[0023] The top handle 40 includes a gripping part 43 extending in the longitudinal direction between the front end part 41 and the rear end part 42. The gripping part 43 is slightly inclined obliquely downward as extending from the front end part 41 toward the rear end part 42 of the top handle 40. 

45 

[0024] The gripping part 43 is a part to be gripped by the operator when the operator holds the chain saw 1A. The operator puts the hand into a space between the gripping part43 and the uppersurface ofthe body part11. 

50 

[0025] The gripping part43includes a triggerlever43a as operating part to increase or decrease the rotation speed of the saw chain 22 and a lock release lever 43b to unlock the trigger lever 43a, in a state where the op- erator grips the gripping part 43. 

55 

[0026] As shown inFIG.2,a thumb rest45 isarranged on the upper surface of the front end part 41 of the top 

