type washing machine includes a cabinet 1 defining an external appearance of the drum type washing machine a tub 2 installed in the cabinet 1 in a shock absorbing manner using a damper 4 a drum 3 rotatably disposed in the tub 2 and having dehydrating holes 3 b perforated in a peripheral surface thereof a shaft 5 connected to the drum 3 through the center of a rear wall 10 of the tub 2 and serving to rotate the drum 3 a motor 6 mounted underneath the tub 2 and a power transmission device 7 to transmit drive force of the motor 6 to the shaft 5 the power transmission device 7 includes a driving pulley 7 c fixed to a rotating shaft 6 a of the motor 6 a driven pulley 7 a fixed to the shaft 5 and a belt 7 b to link the driving pulley 7 c and driven pulley 7 a with each other the driving pulley 7 c takes the form of a hollow cylinder and is fixed to a distal end of the rotating shaft 6 a the driven pulley 7 a is fixed to a distal end of the shaft 5 penetrating the rear wall 10 of the tub 2 the tub 2 has a cylindrical shape and includes a front tub 2 a and a rear tub 2.