A pulverizer has a shell having an inlet port for introducing air and the material to be pulverized into the shell and a discharge port through which the pulverized product is discharged from the shell. The shell is filled with a pulverizing medium such as steel balls. A vertical screw shaft having a screw blade thereon is rotatably mounted in the shell. The screw shaft is hollow and provided at the bottom end thereof with an outlet port. The outlet port is located behind the screw blade with respect to the direction of rotation of the screw shaft. A fluid supply box is provided at the bottom of the screw shaft and extends from the screw shaft to the outer edge of the screw blade. The outlet port is formed in the fluid supply box. A scrape plate protrudes downwards from the bottom end of the screw shaft. Three or more screw blades may be provided.