Reflecting type of zoom lens

A reflecting type of zoom optical system comprising:

• at least one of (a) a first plurality of optical elements each of which includes a transparent body and two refracting surfaces and a plurality of reflecting surfaces formed on the transparent body, and each of which is arranged so that a light beam enters the transparent body from one of the two refracting surfaces, repeatedly undergoes reflection by the plurality of reflecting surfaces, and exits from the other of the two refracting surfaces, and (b) a second plurality of optical elements on each of which a plurality of reflecting surfaces made from surface reflecting mirrors are integrally formed, and each of which is arranged so that an entering light beam repeatedly undergoes reflection by the plurality of reflecting surfaces and exits from the optical element,
• wherein an optical element of said at least one of said first and second pluralities of optical elements which the light beam from an object enters first has an entrance pupil positioned on an object side of the first reflecting surface, when counted from the object side, and an image of the object is formed via said at least one of said first and second pluralities of optical elements and zooming is performed by causing at least two optical elements from among said at least one of said first and second pluralities of optical elements to vary their relative positions,
• wherein at least one of the plurality of reflecting surfaces of each of said second plurality of optical elements is a curved surface.