The present invention improves reliability of an in-vehicle electronic device against corrosive gases. A trapping agent that has trap performances (adsorptive performance, suction performance, absorption performance, chemical reactivity, etc.) that are higher than that of water vapor with respect to corrosive gases other than water vapor is held within a connector having a terminal that is insert-molded in a case housing an electronic circuit. Here, the trapping agent may be held in a counterpart connector of the connector integrally formed in the case.