Abstract: A stirring device having a casing for forming a stirring chamber, a driving rotary shaft disposed in the casing, a plurality of stirring paddles fitted on the rotary shaft as being dispersed axially of the shaft and a plurality of projections attached to an interior wall surface of the casing. The projections are provided adjacent each other at least one in number on each operational track of a leading edge of the paddle so as to remove excess substance adhered to the paddle thereby preventing frictional wear of the casing by the substance. Also, because of an interspace provided between an axially adjacent pair of projections, the projections do not obstruct the stirring operation of the device.