To provide a photoelectric device for facilitating the control of an aircraft at an approaching stage to a runway when a visual field is not clear, especially at the time of landing.

A photoelectric device includes an artificial horizon 1, a small aircraft index 2, a posture bar 3, and a collimator for displaying a gradient scale 5 which crosses the artificial horizon 1 and is extended to both sides at the position of a course selected by a pilot. The gradient scale 5 is displayed in the form of a dotted line consisting of points arranged at an equal interval of one degree of gradient, and information regarding the selected course and the gradient can be provided to the pilot, and at the same time the inclination in vertical direction can be accurately judged according to the scale 5.