The present utility model discloses a lancing device having a shell, a lancet holder, a triggering mechanism and a triggering force providing unit. The shell has a through hole formed through the sidewall thereof. The lancet holder is mounted in the shell to receive a lancet. The triggering mechanism is mounted in the through hole of the shell to actuate the lancet to be triggered or not. The triggering force providing unit pushes the lancet holder to provide longitudinal force for the movement of the lancet holder. Since the triggering mechanism is mounted in the through hole of the shell, the triggering mechanism is kept from protruding out of the shell so that is not triggered accidentally and does not influence the appearance. Further, it can also keep the dust and water drop from falling into the shell.
