Provided is a hydrometallurgical process for nickel oxide ore using high pressure acid leaching to be capable of achieving improvement of durability of production facilities, simplification of the production facilities, suppression of the cost and environmental risks caused by compression of the volume of a tailings dam that stores wastes, and separation and recovery of impurity components which can be utilized as a resource. The hydrometallurgical process for nickel oxide ore of recovering nickel and cobalt using the high pressure acid leaching is characterized by including at least one step selected from step (A) (a step of separating and recovering chromite particles), step (B-1) (a step of neutralizing a leachate with a magnesium-based neutralizing agent), and step (B-2) (a step of neutralizing a leach residue slurry with the magnesium-based neutralizing agent).