To provide a new granulating process for highly soluble crystalline particles hard to be granulated.

In a granulating process, the wetting action and the impact action are applied only to a small part of a material to be treated at all time, and also a quick drying operation is applied successively thereon to prevent the harmful increase of a water content in powder. In the process, a granulating liquid is sprayed to particles while the particles are affected by quick revolving and rising flows in a vertical pipe 7 to bring the particles into contact with one another and dry them. The excessive permeation of a coating liquid into the interior of particles is prevented by the quick drying. The operational advantages are generated by the low water content during treatment, and the advantages of discontinuing or reopening the operation can be carried out at any time.