A semiconductor device having a functional circuit block with predictive power controller is provided so as to construct a system LSI manufactured in a practicable number of design steps, which is extensible and in which power is reduced. The functional circuit block includes a prediction circuit and a predictive power shutdown circuit having a power status control circuit. The prediction circuit controls a power status of the functional circuit block by using the power status control circuit, based on input information thereto. When no information is inputted for a predetermined a period of time, the power status control circuit shifts from a power status of the functional circuit block to a low-power status.