PURPOSE: To normally carry in/out a vehicle even in cold outdoor environment.

CONSTITUTION: An electric heater H2 is fitted to the surface or rear surface of a traversing guide rail L2 of a first conveyor unit 6 and an electric heater H3 is fitted to the surface or rear surface of a longitudinary traveling guide rail L3 of a second conveyor unit 13. A power supply device is provided for shutting off power supply to the heaters H2, H3 when the conveyor units 6, 13 are driven. Consequently, by applying power to the heaters H2, H3, snow laid on the guide rails L2, L3 is melted and ice thawing can be performed, and therefore a vehicle can be normally carried in/out even in winter. By shutting off power supply to the heaters H2, H3 at the time of carrying in/out of the vehicle, power receiving capacity can be suppressed under used power at the time of carrying in/out and necessity for providing extra power receiving equipment for a rail heating means can be dispensed with.