A transmitter having a structure causing no complicated manufacturing process and no damage of a sealing rubber and capable of certainly preventing an electronic substrate from coming off in exchanging a battery is provided. An inner plate is a component, which has a bending type of unseparated segmentation structure and which is molded into one body, and the inner plate is molded with protruded portions engaging with grooves formed in an inner surface of an upper case and elastic pieces engaging with a periphery of the electronic substrate. The bent inner plate is placed on the electronic substrate and a force for canceling the bending state is added so that the protruded portions would engage with the grooves of the upper case and the elastic pieces would engage with the periphery of the electronic substrate.