The present invention relates to a dishwasher. The dishwasher, according to one embodiment of the present invention, comprises: a wash tank that forms a space for washing dishes; a water supply device having a water chamber for collecting externally supplied water for washing dishes; a sump for receiving water from the water chamber and supplying washing water to the wash tank; and a heat exchange flow channel for exchanging heat with the washing water from the water chamber as the washing water flows from the sump through said channel.