For fixing an object to a fixing plate by a fixing portion of the object and a fixing member, a fixing device includes a first screw member formed on the object and a second screw member corresponding to the first screw member. The fixing member includes a bottom plate portion provided with a through hole allowing a threaded portion of the second screw member to pass therethrough and a plurality of spring portions extending from the bottom plate portion in one direction. The bottom plate portion has an outer dimension smaller than a fixing hole formed on the fixing plate. A combination of the spring portions extends in the one direction from the bottom plate portion having an outer dimension greater than the fixing hole in at least an upper part thereof. Each of the spring portions has lateral sides provided with cut-away portions formed by cutting the lateral sides from the bottom plate portion in the one direction.