[Problem] To sufficiently ensure the capacity of a grass accommodation unit.[Means for Resolution] Since an accommodation unit 14 is provided with a concave portion 50 and a rear bottom surface 14b is disposed at the downside in relation to a front bottom surface 14a, the capacity of the accommodation unit 14 can be ensured while avoiding a radiator 13protruding upwardly. Further, since the rear portion of the accommodation unit 14 is provided with a door 81 opened and closed to eject grasses therethrough and the rear bottom surface 14b is disposed at the downside in relation to the front bottom surface 14a, grasses can be satisfactorily ejected from the rear portion of the accommodation unit 14 toward the front portion thereof when the grasses are ejected.
