A kind of safety lancing device has a front cap and lancet holder with feature: the front cap and lancet holder are connected in insert-plug type, and the front cap is equipped with connecting block at connection end and the lancet holder is equipped with slot at connection end. And the slot includes slideable slot and deadlock slot. The slideable slot is located in front of deadlock slot. The latch is set at the flexible arm end of ejection pin and the latch is equipped with bayonet at the front end and equipped with latch hook at rear end the width of slideable slot and deadlock slot is larger than that of latch the slideable slot is equipped with a blocking shoulder at rear end and the deadlock slot is equipped with latching shoulder at front end.
