A semiconductor integrated circuit includes a limiter circuit for outputting a voltage determining flag in order to set a boosted voltage level of a booster circuit to be a predetermined value, and a monitoring circuit for monitoring a monitoring node of the limiter circuit to output a monitoring signal for the stabilization of a boosted voltage to a first external terminal. The monitoring circuit detects a first level change of the voltage determining flag from “H” to “L” after the starting of the operation of the limiter circuit, by means of a comparator, to which an external power supply voltage and external reference voltage supplied from second and third external terminals are given, and thereafter, outputs a monitoring signal for holding a constant logical level during the operation of the limiter circuit. In order to provide a voltage trimming function, a voltage intended to be set in an external terminal may be given from the outside to deactivate a feedback system of the limiter circuit to operate a resistance value of the limiter circuit to detect and store a limiter flag. Thus, there is provided a semiconductor integrated circuit capable of simply monitoring the output voltage state of an internal power supply circuit by the external terminal and easily trimming an internal voltage.