The present invention discloses a rewritable phase-change optical disk having a recording material of a five-element alloy, Te--(Ge,Bi,Sb)--X, wherein X is B (boron) or C (carbon); Te (tellurium) ranges from 47 to 60 atomic percentage (at. %); Ge (germanium) ranges from 12 to 48 at. %; and Si (silicon) together with Sb (antimony) range from 5 to 41 at. %, based on the total atomic number of Te, Ge, Bi and Sb; and B or C range from 0.05 to 4 at. %, based on the total atomic number of Te, Ge, Bi, Sb and X.