PURPOSE: To do disentangling work and mixing work of a material to be mixed at the same time and to do a uniform, automatic mixing work in a short time.

CONSTITUTION: The mixing device has a semispherical vessel 1 whose circular opening 2 is subjected to position change from a upward horizontal position to a vertical position by a position control mechanism, a rotor R also serving as the cover of the opening 2 of the vessel 1, an agitating blade 9 turned along the inner side wall of the vessel 1 and having an angle for scraping up a material to be mixed in the vessel into piles in the central direction of the vessel 1, and an agitating pin 9 revolving in a turning locus line of the agitating blade 7, and is provided with a rotary agitating device 5 by which the agitating blade 7 and the agitating pin 9 enter and retreat from the opening 2 of the vessel 1 in the axial direction orthogonal to the inclined angle.