The present invention comprises: a slope (22) which has a main plate (34) that changes position between a low position and a high position and a control unit (100) which controls the changing of the position of the slope (22). The control unit (100) has: a first mounting detection means (110) which detects a state of being mounted or a state of not being mounted by a wheelchair (26) with regard to the main plate (34) a second mounting detection means (120) which detects a state of being mounted or a state of not being mounted by a wheelchair (26) with regard to a ground side plate (38) a third mounting detection means (130) which detects a state of being mounted or a state of not being mounted by a wheelchair (26) with regard to a vehicle side plate (36) and a ground detection means (140) which detects whether the end of the ground side plate (38) at the rear side with respect to a vehicle is in contact with a ground surface (20).