A camera exposure control device reduces battery power consumption during film exposure at the picture shooting time for long exposure times greater than several seconds such as bulb shooting and time shooting. The camera exposure control device includes a power source line from a battery power source to a control device and the like. A DC/DC converter is also on the power line. The control device stops operation of the DC/DC converter during the long exposure time where the shutter time is longer than a predetermined time. In other words, the control device controls the operation of the DC/DC converter during film exposure at shooting times where the film exposure time is longer than several seconds. The control device interrupts the DC/DC converter during these long exposure times. Further, other electric parts such as IC's and devices that do not require electricity supplied during the long exposure times can be turned off by the control device.