By providing pressing parts and a transmitting opening part to a cover for covering a key operation part and a transmitter of a housing by sliding, the key operation and the communication in carriage and in ten key operation are enabled, respectively. Moreover, the pressing parts can press different keys in carriage and in ten key operation. Locking nails are provided at the tip of a bowl-like shape, elongating form the end of the cover so that the locking nails are engaged with locking parts for locking with respect to the housing both in the carriage state and in the ten key operation state.