NOVELTY - A composite powder in which powders are coupled is prepared by carrying out application of mechanical action of compressive force and shearing force with respect to the raw-material powder consisting of at least 2 types of powders chosen from metal, metal oxide, metal salt, and metal organic salt. The obtained composite powder is heat-processed to obtain a complex oxide powder. The application process is carried out using a powder processing apparatus (50) in which initial-stage process and late-stage processes are carried out at differing speed.    USE - Manufacture of complex oxide powder e.g. lanthanum group perovskite type oxide (claimed) for use as air pole material of solid oxide fuel cells.    ADVANTAGE - The method enables manufacture of complex oxide powder using reduced number of processes, without formation of aggregates. Generation of powder retained without receiving forceful mechanical action is prevented.    DETAILED DESCRIPTION - A composite powder in which at least 2 types of powders are coupled is prepared by carrying out an applied process of mechanical action which includes compressive force and a shearing force with respect to the raw-material powder consisting of at least 2 types of powders chosen from metal, metal oxide, metal salt, and metal organic salt. The obtained composite powder is heat-processed to obtain a complex oxide powder. The application process is carried out using a powder processing apparatus consisting of a rotary component (2) equipped with blades (3) at the outer periphery, and a casing (1) provided with a cylindrical internal peripheral surface which adjoins with the radial direction tip portion of the blades. The blades adjoined along the axial center direction of the rotary component are extended in directions which are mutually different from the axial center (X). At least one set of blades adjoined along the axial center are mutually inclined in reverse with respect to the axial center. Initial-stage process of application process is carried out by rotationally driving the rotary component at rotational speed (I) with respect to the raw-material powder. Late-stage process is carried out by rotationally driving the rotary component at rotational speed (II) higher than speed (I).    DESCRIPTION OF DRAWING(S) - The drawing shows a partially broken side view of the powder processing apparatus. (Drawing includes non-English language text)    Casing (1)    Rotary component (2)    Blades (3)    Powder processing apparatus (50)    Axial center (X)