A chain saw, arranged with a guide plate and a chain. The chain saw includes a housing, a drive assembly arranged in the housing, and a fixing assembly tensioning the chain and locking the guide plate. The fixing assembly includes a shield abutting against the guide plate, a knob arranged on an outside of the shield, a tensioning member driven by the knob, a locking member snapped to the shield, and an elastic member disposed between the knob and the locking member. A side of the shield facing the locking member is arranged with a first clamping part, and a side of the locking member facing the shield is arranged with a second clamping part; in condition of the guide plate being locked, the elastic member deforms and abuts against the locking member, causing the second clamping part to snapped to the first clamping part.