A conveyance device using a carriage having an object support base movable vertically controlled by cam rails on the floor side, has an automatic lock for locking the object support base at a rising limit position. Unlocking cam follower rollers of the automatic lock are provided higher than a conveyance carriage supporting level of a carriage traveling path. A cam follower roller for elevating the object support base is positioned higher than the conveyance carriage supporting level when the object support base is at the rising limit position. In an area in which the carriage traveling path and the aisle cross each other, a crossing aisle floor member is laid at the same level as the conveyance carriage supporting level, and the conveyance carriage can pass through this aisle crossing area in a state that the object support base is locked at the rising limit position by the automatic lock.