Abstract: A heat exchanger includes a plurality of parallel spaced-apart fins and refrigerant-conducting tubes extending perpendicularly therethrough in a zigzagged arrangement. Slits are formed in each fin wherein there is a pair of slits directly in front of each pipe, a pair of slits at an upper front portion of the pipe, a pair of slits at a lower front portion of the pipe, a pair of slits at an upper central portion of the pipe, a pair of slits at a lower central portion of the pipe, a pair of slits at an upper rear portion of the pipe, a pair of slits at a lower rear portion of the pipe, and a pair of slits directly behind the pipe. The two slits of each pair extend from opposite sides, respectively, of the fin without any space formed between the slits, whereby the slits form contiguous air-conducting passages.