A medical device includes: an insertion portion that includes a distal end and a proximal end and is capable of being inserted into a body； a light-emitting portion that is disposed at the distal end of the insertion portion and is configured to emit light containing a wavelength capable of passing through a biological tissue； and a marking portion that is disposed at the distal end of the insertion portion and is configured to form a marking on the biological tissue. The light-emitting portion and the marking portion are disposed at the insertion portion such that a positional relationship between the light-emitting portion and the marking portion can be fixed.
