PURPOSE: To provide a top/bottom discriminating device which requires no electrical processing and has simple constitution at low cost by providing a frame body which is set at the front of the image pickup area of an image pickup element and coaxially to the optical axis and also holds a ball which can freely roll along the inner circumference of a track and shows the direction of gravity.

CONSTITUTION: The track 1b having an approximately oval cavity, for example, is set at the center of a frame body 1a, and a steel ball 1c can freely roll along the inner circumference of the track 1b. The track 1b has such a shape of a circle, etc., so that the ball 1c can easily roll along the inner circumference of the track 1b. The ball 1c is always positioned at the lower part of the track 1b by its gravity, and the image of the ball 1c is projected on a monitor screen. The position of the ball image always shows the upper direction of an object on the monitor screen. When the camera is turned in its photographing mode, the image of the ball 1c turns in the opposite direction to the camera turning direction on the monitor screen. In other words, the camera turns counterclockwise when the ball image turns clockwise on the screen.