A supporting structure for a lens barrel includes an annular ring having an axis and a circumferential engagement surface provided circumferentially around the axis; a first ring having an engagement surface around the axis which contacts the annular ring engagement surface and is mounted radially inwardly of the annular ring for rotational movement relative to the annular ring; a second ring supporting an optical element, the second ring having an engagement surface provided around the axis, contacts the annular ring engagement surface and is mounted radially inwardly of the annular ring for rotational movement relative to the annular ring, the second ring being capable only of axial movement relative to the first ring; and a biasing arrangement which urges the first and second rings in opposite directions and biases the first and second ring engagement surfaces into contact with the annular ring engagement surface.