In order to place a coherence gate as close as possible to a object, provided is a tomographic image photographing apparatus including: a moving unit for moving the coherence gate corresponding to a difference between an optical path length of measuring light and an optical path length of reference light； and a control unit for controlling the moving unit so as to further move the coherence gate from a second position based on first combined light and second combined light of the object, which are respectively acquired at a first position of the coherence gate and the second position at which the coherence gate is placed after being moved from the first position to the object side by the moving unit.
