A semiconductor integrated circuit is capable of being supplied with battery current information and battery voltage information. The semiconductor integrated circuit includes a memory function, a current integrating function, a voltage-based state of charge operating function, a current-based state of charge operating function, a comparison determination function, a correcting function, and a resistance deterioration coefficient output function. The memory function stores the relation between a state of charge of a battery and an internal resistance deterioration coefficient thereof. The full charge capacity outputted from the correcting function and the internal resistance deterioration coefficient outputted from the resistance deterioration coefficient output function are stored in the memory function when a voltage-based state of charge and a current-based state of charge compared by the comparison determination function are determined to substantially coincide with each other.