A battery car 25 which supplies electrical power to a running motor 16 and a mower motor 15 is included, wheels 34, 38 for facilitating the movement is attached to the battery car 25, and the battery car 25 is connected to a rear portion of a chassis 11 in a freely attachable and detachable manner. Moreover, a bracket 50 for connecting the battery car 25 is included in the rear portion of the chassis 11, and a locking shaft 74 to be connected to the bracket 50 is included in the battery car 25.