A self-scanning light-emitting element array is driven such that, if a current supply line for a light-emitting element is broken, a light-emitting element neighboring failed light-emitting element continues to operate. In first time period turned-on states of the neighboring two thyristor overlap when the turned-on state is transferred in the transfer portion by the two-phase clock pulses; a second time period is provided after the first period, during which the light-emitting thyristor corresponding to the turned-on thyristor in the transfer portion is lighted by the light-emitting signal; in a third time period, after the second time period, a turned-off transfer thyristor for the turned-on thyristor is turned on and the lighted thyristor in the light-emitting portion is lighted out. The second time period has a length in which the thyristor having the broken line neighboring the failed thyristor is lighted.