  The paper demonstrates the geometric optic properties of the transition
radiation (TR) of an ultrarelativistic point-like charged particle crossing the
transverse wall of a circular semi-infinite waveguide with ideally conducting
walls. It is shown that the rays forming the TR field emanate from the point of
entry and obey the laws of geometric optics. The TR field at the observation
point is formed from geometric-optical rays multi re-reflected from the
waveguide wall.
