A fin tube type heat exchanger comprising heat transfer pipes (10) which are arranged parallel to each other and plate-shaped fins (1) which are provided so as to be perpendicular to the heat transfer pipes (10), the plate-shaped fins (1) comprising fin collars (2) through which the heat transfer pipes (10) are passed and with which the heat transfer pipes (10) are in contact. Each of the fin collars (2) has bends provided at both the reflared section (3) and the root section (4) of the fin collar (2), and a flat intermediate section (5) is formed between both the bends. The thickness (Tw1) of the reflared section (3) is set to be less than the thickness (Tw2) of the root section (4). The radius (R1) of the bend at the reflared section (3) is set to be greater than the radius (R2) of the bend at the root section (4). The ratio (Tw1/R1) between the radius (R1) of the bend at the reflared section (3) and the thickness (Tw1) of the reflared section (3) is set to be greater than or equal to half the ratio (Tw2/R2) between the radius (R2) of the bend at the root section (4) and the thickness (Tw2) of the root section (4).