The disclosure is directed to an internal pulse generator outputting a signal with a constant pulse width nevertheless of a frequency of an input signal, including a first PMOS transistor, a PMOS second transistor and an NMOS transistor which are connected between a power supply voltage and a ground voltage in series, a latch and an inverter which are connected between an output terminal and a first node as a drain of the NMOS transistor, and a Y-time delay circuit connected between the output terminal and a second node that is a common gate of the PMOS and NMOS transistors.