To provide a foldable chair capable of being folded and piled up.

This foldable chair CH is provided with a front frame 1 provided with a backrest 12 on an upper end part and a front leg 11 extended to the lower part, a rear frame 2 provided with a rear leg 21 and a sliding shaft for which a pivotally attaching member 51 is pivotally attached to the front frame 1 and slidably incorporated inside the rear leg 21 and a seat 3 turnably supported by the rear frame 2 and the front frame 1 and the axis of the rear leg 21 of the rear frame 2 is arranged so as to be almost overlapped with the axis of the front leg 11 of the front frame 1 in a folding direction. Then, the pivotally attaching member 51 is provided with a receiving material recessed part 51d for supporting the front frame 1 of the chair positioned on an upper side at the time of being folded and flatly piled up on the back surface so as to obstruct movement in a horizontal direction and the rear leg 21 is provided with a spacer 4 for supporting the front leg 11 of the chair positioned on the upper side at the time of being folded and flatly piled up so as to obstruct the movement in the horizontal direction.