Abstract: Disclosed is a pump device, comprising a rotor assembly, a stator assembly and a spacer. The pump device has a first inner cavity and a second inner cavity; the pump device has a first housing and a second housing, the first housing partially covers the rotor assembly, the second housing at least partially covers surrounds an outer periphery of the stator assembly; the first housing and the spacer are fixedly connected by means of welding, and the connection position between the first housing and the spacer is sealed; the second housing and the spacer are fixedly connected by means of welding, and the connection position between the second housing and the spacer is sealed; the spacer comprises a first flange portion and a cylinder portion.