A camera which causes a lens unit to move accurately through a cam member is disclosed. The camera comprises a lens unit with movable lenses making up a view finder optical system, a cam member having a cam which engages with the lens unit for driving the lens unit in conjunction with the operation of the image-taking optical system, a first bias member which biases the cam member in one of moving directions of the cam member, and a second bias member which biases the lens unit so as to contact the cam surface.