An exposure calculating device, for use in a camera having a programmed exposure control mode which automatically calculates a shutter speed and a diaphragm aperture value in a programmed manner, is further capable of modifying the combination of calculated shutter speed and aperture value in accordance with the manual operation. The amount of modification value is automatically reset in response to the detection of the operational condition of the camera, such as a detachment of an exchangeable lens, the charging completion of an electronic flash device, the camera exposure control by a camera accessory, and the change of the exposure control mode.