An inclination detecting apparatus includes a light projecting section, a light receiving section and an operating section. The light projection section projects light towards an object. The light receiving section receives lights reflected from at least two points of the object and outputs a photoelectric current signal. The operating section derives a difference between the reciprocals of the square roots of the photoelectric currents output from the light receiving section. An output of the operating section represents an inclination signal of the object. A shake detecting apparatus includes a light projecting/receiving section and an operating section. The light projecting/receiving section is disposed on the rear surface of a camera, so as to project light towards a photographer, receive lights reflected from at least two points on light receiving elements, and output photoelectric current signals for the respective points. The operating section derives a difference between the reciprocals of the square roots of the photoelectric currents output from the light receiving elements. An output of the operating section is used as a hand shake signal.