An injection device is described including a detection unit that includes an electrode that detects electrical characteristics of a biological tissue, a follow-up mechanism that follows motions of the biological tissue, and a puncture unit capable of puncturing the biological tissue. The injection device is configured to administer a predetermined substance to the biological tissue through a hollow portion defined in the puncture unit. A position of the puncture unit is specified based on a position of the electrode. The follow-up mechanism includes a spiral portion spirally extending around the puncture unit, and being stretchable and compressible along an extending direction of the puncture unit. Electrodes are disposed on an annular distal-end projected plane of the spiral portion, as seen from a distal end side of the puncture unit, along a circumferential direction of the puncture unit.
