PURPOSE: To obtain an invariably synchronizing local signal and eliminate the resetting of a synchronous state by making the frequency divider of each local oscillator perform frequency division in the synchronous state according to phase information obtained from a common oscillation signal.

CONSTITUTION: A phase information generator 48 generates pulses in cycles 1/N time as long as the frequency of the oscillation signal 12 of an oscillator 47 and outputs them as a phase information signal 11. A frequency divider 45 divides the frequency of the signal S12 1/N during the supply of the signal S11. Namely, the frequency divider 45 is reset when the signal S11 is inputted, and repeats the frequency dividing operation for the signal S12 after being reset. Through this operation, a 1/N frequency-divided signal 13 is outputted. Frequency dividers 45 and 45' of 1st and 2nd local oscillators 37 and 37' perform frequency dividing operation in the timing of the supply of the signal S11, so even when only one of them is powered ON and OFF, deterioration in line quality due to amplitude variation caused by a phase shift is not generated.