PURPOSE: To improve the transmission efficiency of the communication by reducing the guard time to be set to the transmission signal from a slave station and to shorten the instantaneous interruption time of a voice signal at the time of switching channels on the mobile station device and the base station device for the mobile communication by the TDMA system and performing the time alignment control.

CONSTITUTION: A measurement means 2 measures the electric field intensity of the radio wave from the base station and a reading means 3 reads out a time alignment value from the correspondence list stored in a storage means 1 based on the measured accepted electric field intensity. The list is obtained by the measurement by taking into account the correlation between the accepted electric field intensity and the time alignment value. Then, a transmission means 4 performs transmission to the base station in the transmission timing adjusted based on the time alignment value read out by the reading means 3. The list may be stored in the base station or the time alignment value may be calculated by arithmetic operation.