PURPOSE: To eliminate totally a periodical correction of time and to attain the reduction of labor, by performing the automatic dial transmission to the time signal number and detecting the incoming time signal to perform an automatic correction of time.

CONSTITUTION: A terminal device contains a timpeiece circuit KL, a display DP for time and a dial circuit DC and is connected to a telephone circuit L. The circuit DC has an outgoing action by means of a driving circuit DRD, and at the same time a detector DS detects the time signal supplied via the circuit L. The circuit DRD is controlled by a control part CT to perform the dial transmission to the time signal number. Then the time of the circuit KL is corrected in response to the detection of the time signal.