To provide a loading plate to be taken in/out of a vehicle body, and to easily store an article in a lower side of the loading plate.

This mechanism has the loading plate 10 provided to be movable between a storing position and a drawing position and having a pair of projecting parts 35 at each of the left and right edge parts, a pair of guide parts 54 formed on a vehicle body side to guide the moving of the loading plate 10 without preventing a rise of the loading plate 10, and a pair of rise regulating parts 74 provided on the vehicle body side corresponding to each of the left and right edge parts of a part energized to an upper side based on gravity of the loading plate 10 in a state located at the drawing position, etc. The loading plate 10 and the rise regulating part 74 are in such a relation that each of the rise regulating parts 74 regulates the rise of each of the projecting parts 35 in the state of the loading plate 10 located at the drawing position, etc., and each of the rise regulating parts 74 does not regulate the rise of each of the projecting parts 35 in the state of the loading plate 10 located at the storing position.