  Among more than 200 extrasolar planet candidates discovered to date, there is
no known planet orbiting around normal binary stars. In this paper, we
demonstrate that microlensing is a technique that can detect such planets.
Microlensing discoveries of these planets are possible because the planet and
host binary stars produce perturbations at a common region around center of
mass of the binary stars and thus the signatures of both planet and binary can
be detected in the light curves of high-magnification microlensing events. The
ranges of the planetary and binary separations of systems for optimal detection
vary depending on the planet mass. For a Jupiter-mass planet, we find that high
detection efficiency is expected for planets located in the range of $\sim$ 1
AU -- 5 AU from the binary stars which are separated by $\sim$ 0.15 AU -- 0.5
AU
