Patent ID: 7478963

Claim:
A binding device comprising: binding rings; a holding member having a length that enables the binding rings to be arranged at a distance from one another; and an operating member movably fixed inside the holding member such that respective bases of the binding rings are secured onto a surface of the operating member at a desired distance so as to secure the binding rings to the holding member; wherein the operating member includes a pair of operating pieces which move within the holding member in a longitudinal direction of the holding member; the base of one of the binding rings is secured to one of the pair of operating pieces, and the base of another of the binding rings is secured to the other of the pair of operating pieces; the pair of operating pieces are fixed to the holding member such that abutting edges thereof are maintained in an abutting state at a location spaced from an inner surface of the holding member when the binding rings are closed, and the abutting edges are maintained at a location closer to the inner surface of the holding member when the binding rings are opened than the location of the abutting edges when the binder rings are closed; an opening/closing member arranged to shift the binding rings in an opening direction such that the operating pieces are moved in the longitudinal direction of the holding member within the holding member and are maintained at the location closer to the inner surface of the holding member when the binding rings are opened; and the opening/closing member is made of an elastic member, and the elastic member is provided between a pair of operating pieces defining the operating member and arranged to diagonally cross a direction connecting the bases of the binding rings secured to the operating pieces at a distance so as to move the pair of operating pieces in directions opposite to each other and to maintain an opened/closed state of the binding rings.