A reception unit receives a command which is either a leftward lane change command or a rightward lane change command. A traveling control unit controls the lane change, based on the lane change command. A lighting control unit turns on a direction indicator. A command determination unit causes the traveling control unit to cancel control of both the leftward and rightward lane changes and causes the lighting control unit to turn off the direction indicator, in spite of the reception unit receiving a first lane change command to either leftward or rightward direction as a lane change, and the traveling control unit starting first lane change control, if a second lane change command, which is in a direction opposite to the first lane change, is received before part of the vehicle enters an adjacent lane which is adjacent to a traveling lane where the vehicle travels.