A pump device, in particular an immersible pump device, includes at least one heat exchanger unit which is in at least one operation state configured for a heat exchange between a cooling fluid and a liquid that is to be pumped and which includes at least one cooling duct and at least one shaft receptacle having an axial direction, wherein a cross section surface area of the cooling duct changes by maximally 200% at least over a major portion of a course of the cooling duct.