A semiconductor integrated circuit device is provided, the circuit being capable of arranging a control signal system, avoiding a danger of failure to check an indefinite signal propagation prevention circuit or the like, further facilitating a check oriented to mounting on an automated tool, and facilitating power shutdown control inside of a chip. In the semiconductor integrated circuit device, power shutdown priorities are provided by independent power domains Area A to Area I. A rule is provided, the rule defining that, in the case where a circuit having a high priority is turned ON, a power domain having its lower priority cannot be turned OFF, thereby facilitating a designing method. In addition, areas capable of applying still another power supply are provided in the independent power areas Area A to Area I. In that area, a relay buffer (repeater) and a clock buffer or an information retaining latch for saving information are integrated. A layout may be provided in a direction vertical to a direction in which cells are arranged in a row direction for the purpose of dispersing a current of a light supply line.