A connecting structure includes a housing, a cooler, an inner refrigerant pipe, an outer refrigerant pipe, and a joint pipe. The joint pipe is attached to a through hole of the housing. The inner refrigerant pipe is fitted to the joint pipe from a housing inner side. The outer refrigerant pipe is fitted to the joint pipe from a housing outer side. A tip of the inner refrigerant pipe and a tip of the outer refrigerant pipe define a gap inside the joint pipe. An end surface of a flange or a rib of the outer refrigerant pipe in a refrigerant-pipe axis direction abuts with an end surface of a flange or a rib of the joint pipe in the refrigerant-pipe axis direction.