A pump unit includes a micro pump and an assist mechanism. The micro pump includes: a housing having an inflow port and an outflow port； and a pump device built in the housing, the pump device transporting a fluid from the inflow port to the outflow port. The assist mechanism includes a jet nozzle for jetting a fluid. A jet port is opened at a tip portion of the jet nozzle. The assist mechanism is disposed in such a manner that a gap through which a fluid outside can flow is formed between the tip portion and the housing. The jet port is located in proximity to the inflow port. The jet port directly faces the inflow port.
