A provided flash unit includes a light emitting part in the main unit of the flash unit and a distance sensor provided only in the light emitting part, achieving an accurate measurement of a distance from a subject. In the flash unit according to the present invention, the light emitting part (10) includes a light receiving element (6) that measures reflected light when light is emitted in advance from the light emitting part (10) to a subject (T) and reflected light when light is emitted in advance from the light emitting part (10) to a reflector (X) for bounce photography, the flash unit determines and controls a proper tilt angle (θ3) of the light emitting part (10) relative to a main unit (9) based on a distance (La) from the subject (T) and a distance (Lb) from the reflector (X), the distances being measured based on the detection by the light receiving element (6), and directivity for the detection by the light receiving element (6) is tilted toward the main unit (9) with respect to a horizontal direction.