A novel wire harness connecting structure for a housed circuit assembly is provided. The connecting structure is able to electrically connect a wire harness and a circuit assembly housed in a housing to each other, using a small number of parts, with high space efficiency. The wire harness connecting structure for housed circuit assemblies is used to electrically connect wire harnesses to circuit assemblies housed in a housing, wherein through holes are provided in a wall of the housing, circuit assembly connectors that are provided in the circuit assemblies face the through holes, and harness end connectors that are provided at ends of the wire harnesses are configured to be inserted into the through holes of the housing and to be connected to the circuit assembly connectors of the circuit assemblies.