PURPOSE: To provide a rotary roller in a kneader in which the roller in the kneading vessel is given revolution and rotation to knead and adjust a particulate matter and can rotate even for a kneading raw material of a small resistance value.

CONSTITUTION: This rotary roller device in a kneader is provided with a plate fixing a blade 9 for generating thrust in a roller body 6 and has internal construction (air supply hole 1, air jet hole 4) by which compressed air is supplied to the plate fixing the blade 9.