Abstract: A stirring blade includes a first member having a first flat surface and a second member having a second flat surface, wherein the stirring blade is rotatable about a rotational axis in a state where the first and second flat surfaces are opposed to each other and spaced by a first distance across the rotational axis. When the stirring blade is rotated about the rotational axis with the first and second flat surfaces at least partially immersed in an object to be stirred, the object to be stirred having entered between the first and second flat surfaces is discharged in a direction away from the rotational axis by a centrifugal force and, simultaneously, the object to be stirred is sucked into and between the first and second flat surfaces from a direction along the rotational axis.