This tissue fastening apparatus is a tissue fastener for clamping first biological tissue and second biological tissue so as to be in close contact with each other, including: a first tissue fixation portion, made of an elastic wire wound in a coil, that is locked on the first biological tissue; and a second tissue fixation portion, made of an elastic wire wound in a coil, that is locked on the second biological tissue, the second tissue fixation portion continuing into the first tissue fixation portion, in which when falling off first and second biological tissue necrotized by being clamped between the first tissue fixation portion and the second tissue fixation portion, the tissue fastener moves only from the second tissue fixation portion to the first tissue fixation portion side and falls off.