A disposable incision safety lancet is provided, including a casing (2) and a trigger. It is characterized in that the casing (2) is provided inside with an incision blood-taking mechanism composed of a cam (3), a main swing arm (4), a secondary swing arm (5), a blade (1) and a spring (8). The present invention combines the two arc-shaped tracks obtained from the two swing mechanisms, the main swing arm and the secondary swing arm, via the cam and a toggle pin provided on the cam effectively and interlockingly, thus making the point of the blade incise along a V-formed path composed of two arcs of different shape connected with each other. Compared with the prior art single-swing-arm structure of the incision blood-taking mechanism, such a double-swing-arm structure can move with higher accuracy and controllability. An incision of different blood-taking depth and blood-taking width can be designed by means of changing the difference of change of the radius of curvature of the flange of cam (3) as well as changing the swing radius of the main swing arm (4) and the secondary swing arm (5), which is especially suitable for taking blood from infants' heel.
