A work vehicle includes: a restrainer vehicle speed setter (71) configured to set a restrainer vehicle speed for preventing the switch of a forward/backward travel switching device (23) ; and a switch restrainer (70) configured to (i) permit the switch of the forward/backward travel switching device (23) while a detected vehicle speed is lower than the restrainer vehicle speed and (ii) prevent the switch of the forward/backward travel switching device (23) while the detected vehicle speed is a high speed not lower than the restrainer vehicle speed.