PURPOSE: To enlarge the automatic tuning drawing range by detecting the automatic frequenency tuning signal as well as the synchronous signal.

CONSTITUTION: When the change over from PLL mode to the automatic frequency tuning (AFT) mode operation condition is carried out, as the detecting signal, not only the synchronous signal but also existence of AFT signal is detected by providing AFT signal detecting circuit 29. When PLL mode is changed over to AFT mode, and AFT is received, AFT signal detecting circuit 29 is quickly brought into no signal. Even when the signal detecting circuit 7 can not obtain the horizontally synchronizing signal synchronizing with the flyback pulse, AFT circuit 8 is operated by noises and the like, AFT signal detecting circiot 29 is operated for a fixed time to to operate AFT loop. Accordingly, the error operation such as jump to other channel can be prevented.