US Patent 7239460 Imaging optical unit and image pickup apparatus

An imaging optical unit including a simple and small retracting mechanism and optical members having a small eccentric error and an image pickup apparatus will be provided. The imaging optical unit for guiding light to an image pickup device is structured so that a first holding member, for holding a reflection member for turning a light flux entering from the side of a subject along a first optical axis to a second optical axial direction almost at right angle, rotates freely about a rotating shaft between the retracting position where the first holding member is housed in a lens frame of the imaging optical unit and the using position where it is projected.