A charging device (2, 21, 32, 41, 61, 81) configured to, when the power output from a solar module is equal to or greater than a predetermined value, supply power from a power source to a charging control system (7, 23, 33, 44, 64, 84) controlling charging of a battery (12, 13), and when the power output from the solar module is not equal to or greater than the predetermined value, supply no power from the power source to the charging control system (7, 23, 33, 44, 64, 84), the charging device (2, 21, 32, 41, 61, 81) comprising: a power detection unit (4, 32, 43, 63, 83) which is connected between the solar module and the charging control system (7, 23, 33, 44, 64, 84), and which is configured to receive and detect the power output from the solar module; wherein the power detection unit (4, 32, 43, 63, 83) is configured to be operated to supply the power from the power source to the charging control system (7, 23, 33, 44, 64, 84) for activating the charging control system (7, 23, 33, 44, 64, 84) when the power output from the solar module becomes equal to or greater than the predetermined value, and a power cutoff unit (5, 42, 62) which is connected between the solar module and the power detection unit (4, 32, 43, 63, 83), and which is configured to cut off the power supply from the solar module to the power detection unit (4, 32, 43, 63, 83), wherein the power cutoff unit (5, 42, 62) is configured to cut off the power supply from the solar module to the power detection unit (4, 32, 43, 63, 83) after the power supply from the power source to the charging control system (7, 23, 33, 44, 64, 84) for activating the charging control system (7, 23, 33, 44, 64, 84) has been performed, said power source is further adapted to supply power to the charging control system (7, 23, 33, 44, 64, 84) through a bypass path, and before the power cutoff unit (5, 42, 62) is configured to cut off the power supply from the solar module to the power detection unit (4, 32, 43, 63, 83), power is supplied from the power source to the charging control system (7, 23, 33, 44, 64, 84) through the bypass path. a power detection unit (4, 32, 43, 63, 83) which is connected between the solar module and the charging control system (7, 23, 33, 44, 64, 84), and which is configured to receive and detect the power output from the solar module; wherein the power detection unit (4, 32, 43, 63, 83) is configured to be operated to supply the power from the power source to the charging control system (7, 23, 33, 44, 64, 84) for activating the charging control system (7, 23, 33, 44, 64, 84) when the power output from the solar module becomes equal to or greater than the predetermined value, and a power cutoff unit (5, 42, 62) which is connected between the solar module and the power detection unit (4, 32, 43, 63, 83), and which is configured to cut off the power supply from the solar module to the power detection unit (4, 32, 43, 63, 83), wherein the power cutoff unit (5, 42, 62) is configured to cut off the power supply from the solar module to the power detection unit (4, 32, 43, 63, 83) after the power supply from the power source to the charging control system (7, 23, 33, 44, 64, 84) for activating the charging control system (7, 23, 33, 44, 64, 84) has been performed, said power source is further adapted to supply power to the charging control system (7, 23, 33, 44, 64, 84) through a bypass path, and before the power cutoff unit (5, 42, 62) is configured to cut off the power supply from the solar module to the power detection unit (4, 32, 43, 63, 83), power is supplied from the power source to the charging control system (7, 23, 33, 44, 64, 84) through the bypass path.