Tilting chair

A tilting chair comprising:

• a support board including an integrated seat and a back support which may be elastically transformed backwards when pressure is applied to the back support;
• a frame comprising a back support part, horizontally coupled to an external surface of the back support, a pair of rear legs bent downwards and extending from left and right sides of the back support, a pair of feet bent at ends of the rear legs and extending forwardly, a pair of front legs extending upwardly from front ends of the feet, a bent front side seat support part which extends to upper ends of the front legs to support a front portion of the seat, and a rear side seat support part connected to a center portion of the rear legs to support a rear portion of the seat;
• flanges longitudinally coupled at a bottom surface of the seat;
• a first coupling unit, mounted at a front side of the flanges, which fixes the front side seat support part;
• and
• a second coupling unit, mounted at a rear side of the flanges, which fixes the rear side seat support part;
• and wherein
• the second coupling unit comprises a head part, a tail part and a connecting protrusion formed at an end of the tail part which allows the rear side seat support part to slide along the tail part within a range between the head part and the connecting protrusion.