A charging apparatus comprising: a charging circuit configured to charge a secondary battery; and a control circuit configured to control an operation of the charging circuit, the control circuit including a control unit configured to control the charging circuit so that the secondary battery is charged with a constant current until a time when a battery voltage of the secondary battery goes to a first voltage, control the charging circuit so that the secondary battery is charged with a current smaller than the constant current when the battery voltage goes to the first voltage, and control the charging circuit so that the secondary battery is charged with a constant voltage when the battery voltage goes to a second voltage higher than the first voltage, wherein the control unit controls the charging circuit so that the secondary battery is charged with such a current as to decrease in accordance with a rise in the battery voltage when the battery voltage goes to the first voltage, wherein the control circuit further includes a current detection unit configured to detect a charging current of the secondary battery, and wherein the control unit controls the charging circuit so that the charging current is lowered to a first current value when the battery voltage goes to the second voltage; and controls the charging circuit so that supply of the charging current is stopped when the current value of the charging current goes to a second current value smaller than the first current value, on the basis of a detection result of the current detection unit, characterized in that the control circuit includes a storage unit configured to store information indicating a relationship of a quadratic curve calculated on the basis of the first voltage and a current value of the constant current as well as the second voltage and the first current value, the quadratic curve having a vertex at the second voltage and the first current value, and wherein the control unit controls the charging circuit based on the information so that the charging current is changed in magnitude in a relationship of the quadratic curve from a time when the battery voltage goes to the first voltage to a time when the battery voltage goes to the second voltage. a charging circuit configured to charge a secondary battery; and a control circuit configured to control an operation of the charging circuit, the control circuit including a control unit configured to control the charging circuit so that the secondary battery is charged with a constant current until a time when a battery voltage of the secondary battery goes to a first voltage, control the charging circuit so that the secondary battery is charged with a current smaller than the constant current when the battery voltage goes to the first voltage, and control the charging circuit so that the secondary battery is charged with a constant voltage when the battery voltage goes to a second voltage higher than the first voltage, wherein the control unit controls the charging circuit so that the secondary battery is charged with such a current as to decrease in accordance with a rise in the battery voltage when the battery voltage goes to the first voltage, wherein the control circuit further includes a current detection unit configured to detect a charging current of the secondary battery, and wherein the control unit controls the charging circuit so that the charging current is lowered to a first current value when the battery voltage goes to the second voltage; and controls the charging circuit so that supply of the charging current is stopped when the current value of the charging current goes to a second current value smaller than the first current value, on the basis of a detection result of the current detection unit, characterized in that the control circuit includes a storage unit configured to store information indicating a relationship of a quadratic curve calculated on the basis of the first voltage and a current value of the constant current as well as the second voltage and the first current value, the quadratic curve having a vertex at the second voltage and the first current value, and wherein the control unit controls the charging circuit based on the information so that the charging current is changed in magnitude in a relationship of the quadratic curve from a time when the battery voltage goes to the first voltage to a time when the battery voltage goes to the second voltage.