To provide a charging circuit and a charging method wherein charging can be carried out substantially to the full.

The charging circuit controls a direct-current voltage applied to an input terminal and thereby charges a secondary battery connected to an output terminal by constant current-constant voltage charging. The charging circuit includes a first operational amplifier circuit in which an output transistor is placed between an input terminal and an output terminal and a voltage dividing resistor is connected in parallel with the secondary battery and to which a first reference voltage and a potential of the other electrode of the secondary battery are applied, and a second operational amplifier circuit to which a second reference voltage and a divided voltage of the secondary battery are applied. The negative pole of the second reference voltage is connected to the negative pole of the secondary battery and the output transistor is controlled by both the operational amplifier circuits.