PURPOSE: To surely interrupt a ringer signal even in the case of a fault of a phase detection section with respect to the ringer control circuit interrupting the ringer signal based on the result of phase detection.

CONSTITUTION: A latch section 8 controls a ringer relay 4 in response to a latch output being a ringer relay control signal with respect to a ringer phase signal to apply a ringer signal to a subscriber line synchronously with a ringer phase signal on the occurrence of the ringer relay control signal. The ringer control circuit is provided with a monitor function section 10 to monitor a changing state of the ringer phase signal and provided with a changeover section 11 to select a latch timing of the ringer relay control signal of the latch section 8 in response to the change state off the ringer phase signal. When the ringer phase signal is changed within a prescribed period longer than the ringer period, the ringer relay control signal is latched by the ringer phase signal and when the ringer phase signal is not changed, the ringer relay control signal is latched by other clock sufficiently faster.