A CPU performs a control for photographing a main subject in absence of auxiliary light, whereby an image signal is outputted from an analogue signal processing section. Next, the CPU performs a control for photographing the main subject in presence of the auxiliary light, whereby an image signal is outputted from the analogue signal processing section. An AF area extracting section extracts image signals in an AF area from the image signals. A differential signal calculating section outputs a differential signal between the extracted image signal, and a distance measuring section compares magnitudes of that differential signal and a reference value in a distance data base to calculate distance information based on the comparison result. An AF control section executes AF control of mountain climbing system with the use of the distance information.