There is provided a power transmission device for a working vehicle, in which a drive takeoff shaft for front wheels can be easily mounted on or dismounted from a transmission case and hence the workability of assembly, maintenance, and the like can be improved but the cost of manufacturing the transmission case and the like can be easily reduced. In the power transmission device for a working vehicle provided with: an engine mounted on a running vehicle body having front wheels and rear wheels; a hydrostatic continuously variable transmission for variably transmitting power from the engine; and the transmission case for transmitting a transmission output from the hydrostatic continuously variable transmission, the drive takeoff shaft for front wheels for transmitting a driving force to the front wheels and the hydrostatic continuously variable transmission are arranged on a center plate disposed on the front side of the transmission case.