NOVELTY - A cobalt salt aqueous solution and alkaline aqueous solution are supplied in stirring state into suspension obtained by dispersing nickel-hydroxide powder in water, subjected to by neutralization crystallization process, and surfaces of nickel hydroxide particles are coated with cobalt hydroxide as main component. The resulted product is subjected to oxidation process such that cobalt hydroxide is oxidized by supplying oxygen while stirring the slurry of nickel-hydroxide particles, to obtain coated nickel-hydroxide powder.    USE - Manufacture of coated nickel-hydroxide powder used as positive electrode active material of alkali secondary battery for power supply for electric vehicle, hybrid vehicle and portable electronic device.    ADVANTAGE - The method enables manufacture of coated nickel-hydroxide powder with uniform coating having excellent adhesiveness. The coated nickel-hydroxide powder prevents peeling of coating at the time of paste preparation, and has high electroconductivity. The alkali secondary battery obtained using coated nickel-hydroxide powder has high output characteristics. The portable electronic device has high capacity.    DETAILED DESCRIPTION - A cobalt salt aqueous solution and alkaline aqueous solution are supplied in stirring state into suspension obtained by dispersing nickel-hydroxide powder in water, subjected to by neutralization crystallization process, and surfaces of nickel hydroxide particles are coated with cobalt hydroxide as main component. The resulted product is subjected to oxidation process such that cobalt hydroxide is oxidized by supplying oxygen while stirring the slurry of nickel-hydroxide particles, to obtain coated nickel-hydroxide powder. The pH of suspension solution of nickel hydroxide powder at 25 degrees C is 8-11.5. The ratio (( rho )/(dx v)) of supply rate ( rho ) of cobalt salt aqueous solution, to the product of the flow rate (v) of the suspension solution and supply width (d) of cobalt salt aqueous solution in direction orthogonal to the flow direction of suspension solution in contact portion is 3.5W10-4 or less mol/cm2. The pH of a slurry of cobalt hydroxide-coated nickel hydroxide powder is 12.5 or more, and the cobalt hydroxide is oxidized by supplying oxygen such that total supply amount of oxygen is 30 l/mol or more with respect to the molar quantity of cobalt in coating. An INDEPENDENT CLAIM is included for coated nickel-hydroxide powder, which comprises nickel-hydroxide powder having surface coated with cobalt compound containing mixture cobalt oxyhydroxide or cobalt oxyhydroxide, and cobalt hydroxide as a main component. The cobalt in coating has valence of 2.5 or more.