To provide an auxiliary device that, without adding a special means to a camera main body, makes it possible to check the degree of inclination of the horizontal face of a camera while performing visual observation through a finder during photographing and facilitates accurately leveled photographing.

By mounting the auxiliary device on the accessory shoe of a camera main body, levels are disposed in the auxiliary device. One of the levels is disposed in parallel with the horizontal axis of the camera, the other in parallel with the vertical axis of the camera. The degree of inclination of each level can be visually observed through an eyepiece window via an optical system composed of a combination of lens and mirror. When photographing takes place with the camera in a sidewise position, the level is in a horizontal position. When photographing takes place with the camera in a vertical position, the level is in a vertical position. By viewing and checking the degree of inclination of the camera by means of the levels while viewing a subject in the finder, the inclination of the camera can be horizontally adjusted.