We discuss all possible rephasing invariants of the Kobayashi-Maskawa matrix. We find that all CP-violation phenomena of the KM matrix are expressed by linear or quadratic functions of one special class of nine invariants and the imaginary parts of these invariants are the same with respect to the KM angles and phase i.e. ${C}_{1}$${C}_{2}$${C}_{3}$${S}_{1}$${}^{2}$${S}_{2}$${S}_{3}$ sin\ensuremath{\delta} where ${C}_{i}$=cos${\mathrm{theta}}_{i}$ and ${S}_{i}$=sin${\mathrm{theta}}_{i}$.