  The process e^+e^- ->mu^+mu^- has been studied with SND detector at VEPP-2M
e^+e^- collider in the vicinity of phi(1020) resonance. The product of
branching ratios of phi meson into leptons \sqrt{B(phi->mu^+mu^-) B(phi->
e^+e^-)}=(3.14+-0.22+-0.14)x10^{-4} was measured from the interference in the
cross section of the process e^+e^- ->mu^+mu^-. The branching ratio
B(phi->mu^+mu^-)=(3.30+-0.45+-0.32)x10^{-4} was obtained.
