An acoustic dynamics of a circular micro-meniscus is theoretically studied. The system involves a perfect gas bubble entrapped in a micro-meter-sized cavity, which is fabricated at the end face of a horizontal plane wall submerged in a viscous incompressible liquid. An unsteady Stokes equation for liquid and a linearized energy equation for gas are solved to determine the micro-meniscus oscillation in an untrasound field. The transfer functions, which connect the meniscus oscillation to the liquid and gas normal stresses on the interface, are derived. The frequency response predicted by the present model is consistent with available experimental data on the amplitude of the interfacial deflection. The viscous damping effect on the resonance behavior is discussed.