Puncture device and fine pore formation method

There is provided a puncture device for forming a fine pore on a skin of a subject by striking a needle against the skin, comprising: a piston, wherein the needle is to be attached to a distal end of the piston; a drive spring which has one end capable of contacting a proximal end of the piston, and moves the piston in a specific direction toward the skin; and a first contact section configured at a specific position and including a contact surface capable of contacting other end of the drive spring, wherein the one end of the drive spring and the proximal end of the piston are not fixed to each other, and/or the other end of the drive spring and the contact surface of the first contact section are not fixed to each other; and a length between a supposed strike position and the contact surface of the first contact section is longer than a total of a natural length of the drive spring and a length between the proximal end of the piston and a tip end of the needle, wherein the supposed strike position is where