PURPOSE: To generate abnormal voltage simply by switching-operating either of a switching means for an abnormal-voltage generating circuit or a switching means for a service interruption circuit at predetermined timing and generating abnormal voltage and momentary service interruption in output voltage through a voltage regulating section.

CONSTITUTION: A voltage regulator with an abnormal-voltage generator has a step-up transforms 2 with a tertiary winding, a step-down transformer 3, a turn ratio on the secondary side thereof can be changed, a timing regulating section 15 as a timing generating means switching a contact at prescribed timing and switches 5 and 6 as mutually interlocking changeover switches. When the switch 5 is closed and the switch 6 is connected to the contact (a) side, abnormal voltage corresponding to ON-OFF of a contact for the timing regulator 15 is outputted. When the switch 5 is opened and the switch 6 is connected to the contact (b) side, a momentary service interuption is generated with ON-OFF of the contact for the timing regulating section 15.