The nonlinear oscillation of a bubble in compressible hydraulic oils subject to periodic pulsating pressure was theoretically analyzed. According to the numerical calculations, the effect of compressibility of liquid on the oscillation of a bubble were clarified. That is, (1) the effect of compressibility is appreciable where the amplitude is large; (2) when compressibility is considered, the pressure threshold increases; (3) in the subharmonic of order 1/2, the effect of compressibility on the pressure threshold is almost constant over a wide range of initial bubble radiusR0; (4) the effect of compressibility on the relation between ω/ω0(a ratio of the circular frequencies of pulsating pressure and a bubble) and pressure threshold of the subharmonics 1/2 and 1/3 is almost constant covering the wide range of ω/ω0.