To provide a foot bath using a natural convection system with the heat by an electric heater without using a pump, etc., for circulating foot-bath water, especially allowing a user to take both a foot bath for soaking right and left toes in foot-bath water in a bathtub and a steam bath for warming the toes and shins put in the bathtub with steam, as a foot bath for soaking right and left toes in foot-bath water stored in the bathtub whose top is open, instead of a conventional one structured to spout hot water from a water nozzle by an electric pump to the soles of feet, having a sterilization water tank in which silver ions are dissolved for reducing odors of feet and preventing the athlete's foot.

The bathtub is divided right and left by a center partition, and a control part for controlling the electrification of the electric heater, a steam generating device and a sterilization device is stored in the center partition. The foot bath has a hot-water bath function part for circulating foot-bath water with the heat of the electric heater and a steam bath function part for feeding heated steam to the bathtub, and a switch operation part for selecting whether the hot-water bath function part and the steam bath function part should be selectively operated or simultaneously operated. A steam guide port is located higher than a prescribed level of foot-bath water in the bathtub.