The present invention relates to a puncture device 1 for moving a puncture element 21 in a piercing direction N1 and for piercing a target site with the puncture element 21. The puncture device 1 is for moving a second member 42 retaining the puncture element 21 in the direction N1 and in a direction N2 by the rotational motion of a third member 40 as a first member 41 moves in the directions N1 and N2. The puncture device 1 further comprises a piercing depth adjusting mechanism 6 of adjusting a piercing depth of the puncture element 21 to the target site by regulating a rotation angle of the third member 40.