PURPOSE: To half reduce spots to be calked, ease manufacturing and enable preventing blade pieces from vacillating in such a way that blade plates are integrated with two blade pieces, and the two blade plates are integrally linked with strip plate parts.

CONSTITUTION: Blade plates 7 are formed by bending blade pieces 9, 10 in quasi- face-to-face condition on both sides of quasi-sectorial strip plate parts 8. Then, in case of a blower fan 3 which is integrated by mounting the blade plates 7 on a main plate 4, calked spots are almost half reduced in comparison with the former ones, so that it may be easier in its manufacturing. Besides, since two blade pieces 9, 10 of the blade plates 7 are integrally linked by means of strip plate parts 8, it offers a considerable strength. Thus, it will be induced that the blade plates 9, 10 may seldom vacillate, balance adjustment can be made easier, and it can be prevented from abnormal vibration during its operation.