PURPOSE: To provide the shelf plate fitting device which can reduce a manufacturing cost and a transporting cost, can be assembled easily, and also, has strength.

CONSTITUTION: This device is provided with a shelf support plate 3 connected to the upper end of a fitting plate 1, and a connecting arm 4 connected to the fitting plate 1 and the shelf support plate 3. To one end part of the shelf support plate 3, a horizontal pin 7 is fixed. In the upper part of the fitting plate 1, a guide groove 14 in which the horizontal pin 7 is freely slidable in the horizontal direction, and also, is freely turnable is formed, and in the guide groove 14, a detaining part 15 for controlling a movement of the horizontal pin 7 is formed. A screw hole 16 is formed on the opposed wall surface side from the center of the pin 7 positioned on the wall surface side in the guide groove 14, and also, in a position where a set screw 17 screwed to the screw hole 16 is engaged to the pin 7. In the fitting plate 1 and the shelf support plate 3, recessed parts 10, 20 into which both ends of the connecting arm 4 are fitted are formed.