A steam generator includes: a water storage chamber which stores water therein, at least one heating portion which heats water in the water storage chamber to generate steam, a water supply device which supplies the water storage chamber with water, a steam spout port which spouts the steam generated in the water storage chamber therethrough, and a plurality of fins positioned below the steam spout port in a steam-generating direction and spaced from one another, wherein a first distance between the plurality of fins differs from a second distance between an inner wall side surface of the water storage chamber and the fins.