A power-on reset circuit is provided for generating a power-on reset signal for sequential logics or memory devices as a power supply potential is applied initially. The power-on reset circuit is provided in the same chip as the sequential logics, and generates the signal after an adjustable time interval. The power-on reset circuit includes an oscillator for generating a clock signal, and a counter for counting pulses of the clock signal from when the power supply potential is applied. The time interval is adjusted by loading a preset data value in the counter, which thus outputs a CTR signal when the counted pulses become equal in number to the preset number. A combinational logic circuit resets the counter when the power supply potential is initially applied, and also generates a power-on reset signal when the counter outputs the CTR signal. The power on reset signal further disables the counter, so that the CTR signal is maintained.