To develop a table from a chair, by fixing a slit panel slidable in the vertical direction along a guide pin in the vicinity of the upper end of a support arm onto the back face of a back rest panel.

Guide pins 21, 22 are equipped respectively facing inside in the lateral direction onto upper parts of support arms 12, 13. Slit panels 26, 27 are equipped with slits 24, 25 to be fit by guide pins 21, 22 with play. Slit panels 26, 27 are placed almost vertical against the longitudinal direction of the back rest panel 20 from the lower end to the upper end. This chair 10 is usually used in a condition the back rest panel 20 is erected in the vertical direction. On the other hand, when a table is to be used, the back rest panel 20 is pulled up to the upper dead point and then turned backward at about 90° to make the back rest panel be a table. The upper end faces of support arms 12, 13 erected behind the seat part become stoppers to support the under face of the back rest panel 20 to keep the back rest panel horizontal.