The invention discloses a sparing operating mechanism and an opening pawl thereof. A main connecting lever of the opening pawl is hinged to a rack via a static hinge point. One of two free ends of the main connecting lever cooperates with an opening control piece and the other is hinged with an auxiliary swing arm via a movable hinge point. A pressure spring is connected to the auxiliary swing arm. In this way, when the whole spring operating mechanism is in the state when opening spring stored energy is kept, the auxiliary swinging arm is tightly maintained between the main connecting lever and a keeping connecting lever, and the auxiliary swinging arm passes the dead point state of the static hinge point in the extension direction or the free end of the keeping connecting arm imposes torque in the anticlockwise direction by regarding the static hinge point as the support point on the main connecting lever via the auxiliary swinging arm, so the auxiliary swinging arm is firmly clamped between the main connecting lever and the keeping connecting arm. When the bake is opened, the free end of the auxiliary swinging arm swings relative to the main connecting lever anticlockwise and the swinging space of the free end of the keeping connecting lever is left. Meanwhile, for the whole opening pawl, the swinging amplitude of the auxiliary swinging arm is quite small, thereby increasing use rate of the space of the rack.