Abstract: A battery charger and a battery charge method are provided. The battery charger and the battery charge method allow a battery to be charged in accordance with a charge algorithm optimum for the battery and based on a charge characteristic of the battery acquired at the time of daily charge of the battery. A battery charger includes battery charge means for charging a battery connected thereto based on a predetermined charge algorithm and signal analysis means for analyzing the battery based on a charge signal sent from the battery charge means, and the battery charge means automatically switches the charge algorithm to another in accordance with the state of the battery analyzed by the signal analysis means and repeats the charge a predetermined number of times.