In lower hierarchy design in which a plurality of circuit blocks are independently designed, a reset adjustment circuit propagating deactivation transition of a reset signal to flip-flops in synchronization with a clock signal is inserted immediately after a reset input pin in each circuit block, and timing adjustment using the clock signal as a reference is implemented for signal paths of the reset signal from the reset adjustment circuit to the flip-flops. In upper hierarchy design in which an entire semiconductor integrated circuit is designed, timing adjustment using the clock signal as a reference is implemented for signal paths of the reset signal, according to setup times and hold times of the reset signal that are prescribed respectively for the reset input pins of the circuit blocks.