LOCK STRUCTURE OF BINDER

PROBLEM TO BE SOLVED: To simplify a structure of a binder by simultaneously releasing a binding ring by an action of a spring means which always displaces a rotation shaft for supporting the binding ring of the binder in a shaft line direction. SOLUTION: Opening 22, 22' for locking comprises a 1st opening 23 which can house a lock member 30' fixed on a rotation shaft 16 in a position of a release of a binding ring 12 and, a 2nd opening 25 for locking a lock member 30' at the closing position of the binding ring 12. The lock member 30' has a slope 31' having inclination corresponding to a slope 31. A push member 32 is pushed from a position of closing by a finger. The rotation shaft 16 is pushed in the shaft line direction against a biased force in the shaft line direction so that the lock member 30' is guided to the first opening part by the slope face 31 over a locking face 27 so as to release the binding ring 12.