PURPOSE: To easily form the various kinds of fan blades using a single die set in order to attain the cost reduction, by applying the forming work to the blank of the fan blade, being inserted between the circular arc type male die and female die in a specified angle against the longitudinal axis of these dies.

CONSTITUTION: At manufacturing the fan blade of the steel made cooling fan, the blank 1a of the fan blade is inserted between the circular arc type male die 3 and female die 4 in a specified angle β against the longitudinal axis of these dies 3, 4, and then the blank 1a is subjected to the forming work. By taking above stated angle β suitably, the inlet and outlet angles of the fan blade 1 can be made the specified angles required at every position on the radus from the rotational axis. Hereby, the various kinds of fan blades 1 provided with varied inlet and outlet angles can be easily manufactured by a single die set, so that the cost reduction can be attained.