A gaze point detecting device 1 detects a gaze point of an object person by projecting a display image displayed by an LCD 8 to outside via a finder 4 and capturing an eye image of the object person by a CCD 11 in response to illumination light irradiated toward outside from the finder 4, and the device comprises an optical system 5 arranged spaced only a focal length apart from a display surface 8a on an optical path of an image displaying optical system between the LCD 8 and the finder 4; the optical system 5 being arranged on an optical path of an imaging optical system between the finder 4 and the CCD 11; a telecentric optical system including a diaphragm 9 arranged spaced only a focal length apart from the optical system 5 on the optical path; and a controller 3 that detects a position of the gaze point of the object person based on the eye image captured by the CCD 11.