The present invention provides an LSI which comprises first circuit areas (e.g., an I/O area and a VBAT area) in which power is always held ON, a second circuit area (e.g., a CORE area) capable of ON/OFF-switching of the power, a power control circuit which is provided within the corresponding first circuit area and outputs a control signal for performing power control on the second circuit area, and a reset signal detection circuit which is provided within the corresponding first circuit area and detects an internal standby reset signal or an external standby reset signal to control the operation of the power control circuit.