A semiconductor integrated circuit capable of performing internal oscillation with high precision is provided. The semiconductor integrated circuit has a memory circuit, an oscillator circuit for generating an internal clock signal based on control information held in the memory circuit, a logic circuit for generating control information for causing the frequency of the internal clock signal to coincide with the frequency of an external clock signal, and an electric fuse circuit or a blow fuse circuit capable of storing the control information generated in the logic circuit and uses the internal clock signal for the synchronous operation of the internal circuit. This allows, even when an error (an undesired variation) occurs in the oscillation characteristic (oscillation frequency) of the oscillator circuit due to a process variation, the frequency of the internal clock signal to coincide with the frequency of the external clock signal at a target frequency without necessitating the mounting of an external crystal oscillator or the inputting of the external clock signal.