  A warped extra dimension model predicts an extra scalar particle beyond the
Standard Model which is called a radion. Although interactions of the radion
are similar to those of the Higgs boson in the Standard Model, a relatively
light radion ($\lesssim 100 {\rm GeV}$) is not severely constrained from the
Higgs search experiments at the LHC. In this paper we study discovery potential
of the radion at a photon collider as an option of ILC. Owing to the trace
anomaly of the energy-momentum tensor, both a production of radion in $\gamma
\gamma$ collision and its decay to gluon pair are enhanced sizably. We find
that the photon collider has a sensitivity for discovering the radion in
low-mass region up to $\Lambda_\phi\sim 3 {\rm TeV}$, where $\Lambda_\phi$ is a
scale parameter which suppresses the interactions of radion to the Standard
Model particles.
