A rolling line material prediction and material control apparatus for controlling the material with high accuracy by having a function of simulating the variation course of a process and complementing information to improve the prediction accuracy of a material model. The apparatus has a rolling record information collecting function of collecting rolling record information obtained from a sensor for measuring the state of a hot rolling line and the state of a rolled steel sheet and from the controller for controlling the hot rolling line, process information supplement function for predicting process intermediate information representing the intermediate state of the rolling line not collectable as rolling record information on the basis of the rolling record information, fixed information such as the machine dimensions,; and target information such as on the thickness and width of the rolled steel sheet, material prediction function for predicting the material of the rolled steel sheet in synchronism with the progress of the rolling record information and the process intermediate information on the basis of the rolling record information and the process intermediate information, and material control function of making a control so that the predicted material agrees with the target one.