  We explore signatures of large extra dimensions with a polarized
electron/positrn beam at the Joint Linear Collider (JLC). We point out that
spin informations can be useful to study indirect signals for large extra
dimensions due to spin-2 nature of Kaluza-Klein gravitons. The spin
configurations of the top quark pair production at $e^+ e^-$ and $\gamma
\gamma$ collisions provide an unique testing ground to search for effects of
the large extra dimensions. Especially we show the forward-backward asymmetry
is a good probe at $e^+ e^- \to t \bar{t}$ process and we can define a new
asymmetry observable effective for $\gamma \gamma \to t \bar{t}$ process.
