A stirring and mixing device 110 comprises an introduction pipe 55 which is provided with a powder introduction port 24 and a liquid introduction port 22, an extrusion pipe 60 which is connected to the introduction pipe 55 and extrudes a mixture of powder and liquid introduced through the introduction pipe 55 to its one end portion, a casing 12 which is connected to one end portion of the extrusion pipe 60 and provided with a passage through which a fluid of the extruded mixture is made to flow, and a stirrer 15 which is disposed within the casing 12 and comprised of a shaft portion 14 connected to a drive source 20 and a stirring blade 16 attached to the external surface of the shaft portion 14. A funnel-shaped powder introducing device 57 is attached to the powder introduction port 24, a feeder 54 for conveying powder is disposed in the powder introducing device 57, and the feeder 54 is connected to an oscillatory rotation drive source 53.