When a vehicle enters into the lower portion of a shielding member, a headlamp is switched on, and a condition flag is set to Set 1 which represents a waiting state in which the vehicle exterior is estimated to become bright/dark intermittently. When the condition flag is set to Set 1, when the vehicle enters into the lower portion of the shielding member, the condition flag is set from Set 1 to Set 2 which represents an intermittent state in which the vehicle exterior becomes bright/dark intermittently with high possibilities. When the condition flag is set to Set 2, a switch-off extension time CFE and a switch-off delay time CTF make a time until the headlamp is switched off. As a result, the time until the headlamp is switched off is delayed, and the headlamp is required to remain switched on at portions where the vehicle exterior becomes bright/dark intermittently.