PROBLEM TO BE SOLVED: To provide a transmission case structure that has rigidity to torque variation from an input shaft for transmitting power to a transmission case.SOLUTION: A seedling transplanting machine of the present invention includes a leveling device driven by receiving transmission of power from an engine. The leveling device includes: a transmission case to which power from the engine is transmitted a drive shaft protrudingly provided from both side surfaces of the transmission case toward the side and receiving the power from the engine transmitted in the transmission case and a plurality of leveling rotors fixed to the drive shaft. The transmission case includes: a main body for rotatably supporting the input shaft to which the power from the engine is transmitted and having an opening through which the drive shaft penetrating and a lid for rotatably supporting the drive shaft and closing the opening of the main body.
