Top-Squark Study at a Future e^+e^- Linear Collider

We discuss a potential of studying the production and the decay of the lightest top squark (t-tilde_1) in the framework of the supersymmetric standard model at a future e^+e^- collider. In particular, we consider the process t-tilde_1 -> t chi^0_1 (with chi^0_1 being the lightest neutralino) followed by t -> bW. It is shown that, by the study of the angular distribution of the bottom quark (as well as the production cross section of the top squark), properties of chi_1^0 can be extracted. We also discuss that, if chi^0_1 is gaugino-like, the neutralino mixing parameters (i.e., the so-called mu-parameter and tan beta) may be constrained.