A mixing apparatus wherein raw material may be crushed to fine particles of desirous size to be mixed uniformally by multi-layered mixing blocks. The mixing apparatus includes a plurality of mixing units piled up in a housing, and arrays of projections formed at the facing side of the mixing units and located alternately in order to form concentric circles which are not interfered with each other. The mixing units are formed with first and second pairs of upper and lower disks. The arrays of the projections are formed on the outer surface of the pairs of disks, and the fluid passages are formed between the upper and lower disks. The inflow passages are opened to the fluid passages which are formed between the lower disks of each pair and the housing. The outflow passages are formed at the inner surface of the upper disks of each pair and the mixing units are attachable in multiple layers.