There is provided a direct crankshaft of an air compressor for producing compressed air in which a crankshaft is implemented by two crank plates integrally overlapped with each other so that compression cylinders can be arranged in the radial direction to exhibit an excellent air cooling performance, top dead centers and bottom dead centers of the compression cylinders are symmetrically arranged so that the cancellation between pressurizing and vacuuming phenomena and the running of a motor can be smoothly performed, and the motor is integrated with a compression pump so that various driving components such as belts, pulleys, covers, and the like are eliminated and manufacturing costs are remarkably reduced. The direct crankshaft includes crank plates integrated with each other to form an overlapping unit. The overlapping unit has a shaft coupling hole through which a motor shaft penetrates such that the direct crankshaft is directly coupled with a motor.