the switch 8 is inhibited from rotation about a center axis of the hinge apparatus 4 because the base 8 a is engaged with a side wall of the receiving portion 10 a in this state the second contacting portions 8 b 2 are contacted with the conductor portions 5 a the protruding portion 8 c 2 protrudes from the outer peripheral surface 10 b of the cylindrical portion 10 through the cut portion 10 c with this structure the switch 8 is received in the hinge apparatus 4 and therefore the switch 8 need not be arranged at another position thus the electronic apparatus can be designed to be compact in size turning back to fig4 a through 4c and 5 a through 5 c the cam member 9 will be described the cam member 9 has a cylindrical shape with one end as a closed end and is fitted over the cylindrical portion 10 to be rotatable as a result the cam member 9 is faced to the switch 8 in the radial direction the cam member 9 has an outer peripheral surface provided with an engaging portion 9 a to be engaged with the first housing 1 in the rotating direction the.