PROBLEM TO BE SOLVED: To provide a lock mechanism for a manual sharp-edged tool that does not touch an opposite grip when releasing a lock.SOLUTION: A lock mechanism for a manual sharp-edged tool for putting a pair of grips into a closed locked state, includes a holding recessed part (8) provided at an end of one grip (4), a locking recessed part (9) provided at an end of the other grip (5), a ring member (10) detachably and rotatably provided in the holding recessed part and putting the pair of grips into a closed locked state, and a valve part (11) for detachably and rotatably fitting the ring member into the holding recessed part. The holding recessed part and the valve part hold the ring member therebetween in a position separated from the other grip when the ring member is removed from the locking recessed part. When the manual sharp-edged tool is used, the ring member is pinched and held by the holding recessed part and the valve part in a position not touching the grip by an operation of removing the ring member from the locked state.SELECTED DRAWING: Figure 1【課題】ロック解除時に反対側のグリップに当たらない手動利器のロック機構を提供する。【解決手段】一対のグリップを閉じたロック状態にする手動利器のロック機構において、一方のグリップ（４）の端に設けられた保持用凹部（８）と、他方のグリップ（５）の端に設けられた係止用凹部（９）と、保持用凹部に着脱可能及び回動可能に設けられ、係止用凹部に係止して一対のグリップを閉じたロック状態にするリング部材（１０）と、リング部材を保持用凹部に着脱及び回動可能に入れる弁部（１１）とを含み、保持用凹部及び弁部は、リング部材が係止用凹部から外された場合に、他方のグリップから離れた姿勢にリング部材を挟持する。手動利器を使用する際、リング部材をロック状態から外す動作によって、リング部材はグリップに当たらない姿勢に保持用凹部及び弁部によって挟持され、保持される。【選択図】図１
