An electronic component unit includes an electronic component having a plurality of terminals that are exposed outside a housing and extend along wall surfaces of the housing, a holding member holding opposite terminals into which the terminals are fitted, and a leakage-blocking structure. The leakage-blocking structure has housing-side wall surfaces provided to the housing of the electronic component and interposed between the terminals adjacent to each other in an alignment direction of the terminals, holding-member-side wall surfaces provided to the holding member and interposed between the terminals adjacent to each other in the alignment direction of the terminals, and overlapping portions formed in such a manner that the housing-side wall surfaces overlap the holding-member-side wall surfaces in the alignment direction of the terminals.