An electric component assembly includes a housing with which an electric component is fitted, and the electric component and the housing are fixed to one surface of a base body. The electric component includes a connection terminal press-fitted to a through-hole (201a) of a board provided in the housing, and an insertion direction of the connection terminal into the through-hole is a fitting direction of the electric component with the housing. The electric component assembly includes a rib which is protrudingly provided on either one of an outer surface of the electric component intersecting the fitting direction and an inner surface of the housing facing the outer surface, and a groove portion which is provided as a recess on another one of the surfaces and the rib is inserted into; and a protrusion that abuts onto the rib is provided on an inner surface of the groove portion.