PURPOSE: To dispense with a casing and thereby aim at the promotion of low- unit cost of production, by installing a lot of blade pieces in a metal plate molding a mixed flow type fan into almost chopper head round sawlike form in a paralflel manner, while installing a flange edge serving as a substitute for a casing.

CONSTITUTION: One metal plate is formed into almost chopped head round sawlike form, while a lot of blade pieces are installed over the whole surface of a molded incline part 1 in parallel at the specified intervals, and a flange edge 3 in proper width is installed in the front side of these blade pieces, opening it, then a boss 5 for receiving a motor rotary shaft is installed in a side plate part 4 at the opposite side. Therefore, the flange edge 3 carries out the role of a casing for air intake. In consequence, it is able to make a casing unnecessary any longer.