Pump unit and hydrostatic transmission

There is provided a pump unit (100) configured to be capable of transmitting a rotational power from a driving power source which is operatively connected thereto to an actuator through a pair of hydraulic fluid lines. The pump unit includes: an input shaft (220); a hydraulic pump main body (300a,300b); a PTO shaft (610); a PTO clutch mechanism (600A); an auxiliary pump main body; a suction line; a discharge line; a charge line; a PTO hydraulic fluid line; a pressure-reducing valve; and a resistance valve. The PTO hydraulic fluid line and the charge line are fluidly connected to the primary side and a secondary side of the pressure-reducing valve, respectively.