PROBLEM TO BE SOLVED: To facilitate a maintenance work in a transmission mechanism, in which a drive power is transmitted to a mowing part through an outputting endless rotator.SOLUTION: A relay transmission shaft 71, to which the motive power of an engine is transmitted, is provided with: an input rotary body 135a, to which the motive power of the engine is inputted through an inputting endless rotor 70 and a mowing output rotor 135b for transmitting an input power through an outputting endless rotor 73 to a mowing part, and the mowing output rotor 135b is disposed closer to the shaft end side of the relay transmission shaft 71 than the input rotary body 135a.SELECTED DRAWING: Figure 13