To provide a method for granulating a plastic mixture to be in a prescribed grain size.

The plastic mixture is softened and melted to be granulated by making an agitating shear force act thereon by an agitating blade 2 in a granulating tank 1 and granulates of the plastic mixture are manufactured by cooling the mixture. With the rotation of a motor 5, in this method, an agitation load metered by an ammeter 6 becomes the maximum corresponding to a softening start temperature and then the minimum corresponding to a melting start temperature and increases from the minimum load. In the granulation process wherein the load increases from the minimum, granulation is performed by cooling by a cooling device 4 with a prescribed load made an index. In this granulating method, the plastic mixture may be granulated and cooled in a state wherein a softened plastic component and a melted plastic component are present mixedly. When the temperature of a granulating system corresponding to the minimum load is made the melting start temperature, the granulation and cooling may be conducted at a temperature higher by 20-60°C than the melting start temperature.