Abstract: A heater device particularly for ski boots, which comprises, located on the inner shoe of a ski boot, an electric resistance heater positioned at the user's foot sole and connected to a storage battery accommodated inside said inner shoe. The storage battery is connected to a recharge socket located at the top portion of said shoe and is connected to the resistance heater through a switch. Also provided is a voltage limiter adapted to prevent the storage battery from being discharged to below a preset voltage level.