Abstract: A rotor for fluidic apparatus such as, blowers, compressors, fluidic motors and vacuum pumps includes a drive shaft having concaved portions on its periphery and a rotatable member cast around the concaved portions of the drive shaft. The rotor according to the present invention is manufactured through the steps of forming the drive shaft, disposing the formed drive shaft into the cavity of a molding die, and then pouring the molten metal into the cavity while disposing the drive shaft therein. The resulted rotor has no play in the direction of its rotation of its rotatable member.