There are included a passage portion provided at an upper surface portion of a mower deck, front and back slope portions and provided at front and back portions of the passage portion, front and back supporting portions supporting the slope portions in such a manner that the slope portions are movable in the front-back direction and swingable in the up-down direction, and front and back linking portions that are supported in such a manner as to be swingable in the front-back direction about axes extending in the left-right direction and that are connected with the slope portions. Operating the front and back linking portions in the front-back direction causes the front and back slope portions to be operated to the storage and use positions.