A clipping instrument for an endoscope is provided. The clipping instrument includes a flexible sheath, an operation wire, at least one detachable clip assembly, including a pair of clipping arms and a fastening ring. The clipping arms are configured to be projected forward to open outside the flexible sheath and to be closed to clip onto a treatment object outside the flexible sheath according to movements of the fastening ring. The clipping instrument further includes a sleeve formed to have a plurality of slits and a blade spring piece to be attached to the sleeve. The sleeve includes a plurality of blade springs, each of which is settled in one of the plurality of the slits of the sleeve when the blade spring piece is attached to the sleeve. The plurality of blade springs can resiliently hold the detachable clip assembly in a posture with respect to the flexible sheath.