Structure and physical properties of a pressure induced superconductor Cs3C60 were studied by X-ray powder diffraction and ESR methods. All X-ray diffraction patterns below 300 K under ambient pressure (1 bar) showed that Cs3C60 took a body-centered orthorhombic (bco) structure as main phase and an A15 structure as minor phase. The ESR at 1 bar showed that Cs3C60 was metallic from 2 to 290 K. The pressure dependence of X-ray powder diffraction showed a disappearance of A15 phase above 20 kbar. The compressibility for the bco phase of Cs3C60, 3.1×10−3 kbar−1, was similar to those of Rb3C60 and K3C60