To protect a horizontal deflection output circuit, in the case of reaching the unexpected state of power interruption, such as service interruption in a television receiver.

A detector 3 for detecting the voltage of a power line 2 for a pulse generating means 1A for horizontal deflection is installed. The detector 3 detects the voltage drop at a level slightly higher than the voltage, where the oscillation of horizontal deflection pulses stop, at the voltage of the power line 2. When the voltage drop is detected, power supply from a power supply 6 to a horizontal-deflection output circuit 4 is interrupted by a power interruption means 5. By doing so, operation under unstable oscillation state can be avoided, and the horizontal-deflection output circuit can be protected surely.