Abstract: We discuss methods to calculate an orbital evolution of an extreme mass ratio binary, i.e. a binary of a galactic black hole and a stellar mass compact object. An inspiralling stage of this system is considered to be an promising source of detectable gravitational waves. Because of the extreme mass ratio, one may approximate the system by a black hole geometry (a Kerr black hole) plus a linear metric perturbation induced by a point particle. Under this approximation, several authors have considered the self-force of the orbital evolution, including the effect of gravitational radiation reaction. On the other hand, we have also recently proposed a radiation reaction formula which is an extension of the well-known balance formula of Press and Teukolsky. The radiation reaction formula gives us a convenient method to calculate the infinite time averaged loss rate for constants of the motion (i.e. orbital energy, angular momentum and Carter constant) by gravitational radiation reaction, with which one may approximately calculate the orbital evolution. Since both methods are approximately equivalent, we discuss the consequences of the orbital evolution from the radiation reaction formula, with special emphasis on the gauge condition and its application to LISA.