A circumferential surface of a lens holder is provided with a reflection member having different reflectance relative to a surrounding portion thereof. An opening is formed in an upper cover at a position confronting the reflection member at a time when the lens holder is kept in an original position being as a close-end position. The upper cover is provided with an optical position detector disposed so as to be adjacent to the opening. The optical position detector optically detects the reflection member via the opening when the lens holder is kept in the original position. Consequently, an original position of a taking lens held by the lens holder is detected.