A charge control circuit for a battery charger that quickly detects an attachment state of a battery pack. The battery charger starts charging a battery pack and performs first and second temperature estimation processes. Then, the battery charger performs a first attachment detection process and when determining whether a battery is connected performs a third temperature estimation process. The battery charger performs a second attachment detection process and when determining whether the battery is connected performs a fourth temperature estimation process. The battery charger performs a third attachment detection process and when determining whether the battery is connected ends a single temperature scan and then repeats the routine starting from the first temperature estimation process.