The chair of the invention includes a cushion, a back and a back support. Either or both of the back and back support are made of a flexible material. The back is perpendicular to the cushion and has an upper connecting portion and a lower connecting portion. The back support is of a substantial L-shape and has an upper end and a protrudent mount. The back support is connected between the cushion and the back for supporting the back. The upper end of the back support fixedly connects with the upper connecting portion, and the protrudent mount movably and pivotally connects with the lower connecting portion, thereby the back support is capable of tilting.