A steam generator includes a water storage chamber that stores water and at least one heating portion that heats the water in the water storage chamber to generate steam. A water supply device supplies water into the water storage chamber. A plurality of fins are provided in the water storage chamber. The water storage chamber has a steam spout port from which the steam generated by the heating portion spouts. The plurality of fins extend along a steam-generating direction under the steam spout port, and are separated from each other and cross the heating portion. The heating portion may be above and below a water surface that emerges in the water storage chamber during heating.