A method of pelletizing powdered solid substance in a fluidized bed in which powdered solid substance is fed and liquid substance is atomized and a gas jet stream for the selective discharge is injected through a selective discharge opening provided at the center portion of a funnel shaped gas distributor to discharge selectively the coarse final pellets. The gas jet sets the solid particles in the bed into a forced circulation flow which has the essential role in dispersing powdered solid and liquid throughout the bed as well as the role in said selective discharge process. This is one of the first patents describing a fluid bed granulation process.