The purpose of the present invention is to improve the assemblability of a transmission device and improve the strength of members in a riding-type farm work vehicle such as a rice planter. The transmission device has a transmission case (9). The transmission case (9) has a two-part structure comprising a deep main body (9a) and a shallow lid (9b) and has disposed therein a shaft, gears, and the like. The main body (9a) has a plate-like intermediate member (87) fixed therein, and the intermediate member (87) is used to support the shaft. Because the shaft support span is shortened, the shaft support strength and shaft durability are improved. Because shaft stability is improved, reattachment of the lid (9b) after removal thereof is facilitated. Therefore, maintenance can be performed easily.
