A power management system for an integrated circuit has a signal line, a management data generating unit connected to the signal line, and a plurality of management data using units each connected to the signal line. The management data generating unit outputs, to the signal line, power management data for managing power consumption in each of the management data using units, the power management data corresponding to the state of the management data generating unit. Each of the management data using units reads the power management data for common use from the signal line and controls power consumed by the management data using unit based on the power management data.