SUSY at High Energy $e\gamma$ and $\gamma\gamma$ Colliders

We investigate the sparticle production processes $e\gamma\goto \sele\sz1$ and $\gamma\gamma\goto \sfermion\overline{\sfermion}$ at high energy $e\gamma$ and $\gamma\gamma$ colliders in the framework of the minimal supersymmetric standard model (MSSM). It will be shown that the $e\gamma$ colliders would be more suitable in searching for the heavy selectrons than $ee$ colliders because of the low mass threshold of the process $e\gamma\goto \sele\sz1$. We show that the standard background processes $e\gamma\goto \nu W$ and $eZ$ can be suppressed in terms of initial beam polarization as well as the kinematical cuts on the energy and angle of the final electron. Moreover, it will be argued that the experimental measurements of the cross sections for the processes $e\gamma\goto \sele\sz1$ and $\gamma\gamma\goto \sfb\sf$ could enable us to constrain the basic parameters in the MSSM. This is originated from the simplicity of SUSY parameter dependence of these processes. We also give comments on the stop production at $e^{+}e^{-}$ colliders with the longitudinally polarized electron beams.