To reduce impact given to a photographing optical system and an extending mechanism while keeping responsiveness in focusing by restricting the extending speed of the photographing optical system to the in focus position when the photographing optical system is positioned near an extending end.

A focus detection means 1 detects focus information corresponding to the focusing state of the photographing optical system Z, for example, a defocusing quantity and a range-finding value, based on a phase difference detecting system, an external light passive system and an external light active system. Then, a focusing means 2 extends the optical system Z to a focusing state based on the focus information. In the midst of such focusing, an end point decision means 3 decides whether or not the optical system Z is positioned near the extending end, and a speed restricting means 4 forcibly restricts the extending speed of the optical system Z in the case the decided result by the means 3 is true.