a mounting apparatus of a flexible board which connects a first electrical member , movable in an optical axis direction , to a second electrical member , which is movable relative to the first electrical member . the apparatus includes a cylindrical support provided between the first and second electrical members , and an axially elongated mounting opening is provided in the cylindrical support , in which the flexible board can be received . an elastically deformable mounting member is fitted in the mounting opening by elastically deforming the same . the elastically deformable mounting member holds the flexible board , which is wrapped around the mounting member , in a manner such that the bent portion of the flexible board is perpendicular to the direction of relative movement of the first and second electrical members .