To prevent a circuit for checking key from being removed from a lower housing (or upper housing).

In a portable transmitter in which a transponder is stored inside a housing, a bottomed hole having a larger depth dimension than opening dimension and a slightly larger dimension than that of the transponder is drilled on a peripheral face of the housing, the transponder is stored in the bottomed hole, and the transponder is bonded on an inner wall face of the bottomed hole.