Structure of chair-back

The present invention relates to a coupling structure of a coupling portion of a back for a chair, wherein a chair comprises a pedestal, a lower support, and a moving support, and a coupling portion is formed to integrally protrude to an external side of the back installed in a back plate support installed in the chair. The coupling portion is fixedly installed in the back plate support with a bolt to be formed independently from a conventional back of a chair as separate independent composition. Without an inconvenience working process of assembling the coupling portion in a coupling hole formed in the back of a chair and fixing the coupling portion to the back plate support with the bolt, the back of the chair in which the coupling portion is integrally formed can be quickly, conveniently, and stably coupled to the back plate support with the bolt. 본 발명은 좌대와, 하부지지대와, 이동지지대로 구성된 의자에 설치되는 등판지지대에 설치되는 의자등받이의 외측에 결합부가 일체로 돌설되게 형성되어 이 결합부를 등판지지대에 볼트로 고정설치되게 하여 기존의 의자등받이에 별개의 독립구성으로 결합부를 구성하여 의자등받이에 형성된 결합공에 결합부를 조립하고 등판지지대에 볼트로 고정하는 번거로운 작업공정을 없애도록하여 결합부가 일체로 형성된 의자등받이를 신속하고 간편하게 안정적으로 등판지지대에 볼트로 결합하도록한 의자용 의자등받이의 결합부 결합구조에 관한 것이다.