A manufacturing apparatus manufactures flattened tube fins in which cutaway portions for inserting flattened tubes for heat exchanging are formed. The manufacturing apparatus includes: a press apparatus with a mold apparatus that forms the cutaway portions in an unmachined metal thin plate to produce a metal strip; an inter-row slit apparatus cutting the metal strip with the formed cutaway portions into predetermined widths to form metal strips of product width arranged in the width direction; and a cutoff apparatus cutting each metal strip of the product width formed by the inter-row slit apparatus into predetermined lengths. A plurality of box-like magazines whose upper surfaces are open are arranged in the width direction downstream of the cutoff apparatus to stack the flattened tube fins formed by the cutoff apparatus cutting into lengths.