A heat exchanger is provided for a refrigerator and includes one or more refrigerant tubes for refrigerant flow, and a plurality of straight fins having lengths different from each other fitted to the refrigerant tubes at fixed intervals in parallel to each other by means of through holes formed therein. The heat exchanger includes sections having different intervals or spaces between fins, wherein sections with the smallest fin spaces have a size 75% or less of a total size of the heat exchanger.