To predict with favorable accuracy a vulcanization degree of a rubber material.

There is provided a method for predicting a vulcanization degree of a rubber material. The vulcanization degree prediction method includes: a measurement step S1 in which a shear resistance torque of a rubber material in vulcanization is measured, and an actual measurement vulcanization cure curve 2 that shows relation between a vulcanization degree X(t) of the rubber material and a vulcanization time t is obtained; and an identification step S2 in which respective constants K₁, K₂ and m are identified so that an error between the actual measurement vulcanization cure curve 2 and a prediction vulcanization cure curve 3 may become the minimum. The identification step S2 includes: a constant calculation step S1 in which two or more real numbers are substituted to the constant K₁, and approximation is performed by the actual measurement vulcanization cure curve 2, thereby the respective constants K₁, K₂ and m are obtained for the respective real numbers; and a curve specifying step in which a prediction vulcanization cure curve 3s in which an error with the actual measurement vulcanization cure curve 2 is the minimum is obtained in two or more prediction vulcanization cure curves 3 obtained from the constants K₁, K₂ and m obtained from the respective real numbers.