The present invention addresses the problem of providing: a mower to which a belt can be easily mounted and demounted; and a working vehicle provided with the mower. A mower is provided with: a mower deck for accommodating a plurality of cutting blades; cutting blade shafts for respectively supporting the cutting blades; driven pulleys affixed to the cutting blade shafts; a gear box supported on the upper surface of the mower deck and reducing the speed of power transmitted from an engine; a drive pulley affixed to the output shaft of the gear box; and a belt wound around the drive pulley and the driven pulley. The gear box is configured so as to be capable of pivoting upward about the side of the drive pulley, around which the belt is wound.
