A method of producing an aqueous solution of slaked lime is disclosed the steps of which includes introducing water into a slaked lime-dissolving apparatus comprising a dissolving tank (1), a water supply piping (2) connected to a lower part of the tank, a stirring blade (3) disposed within the tank in its bottom part, an effluent piping (6) connected to an upper part of the tank for discharging aqueous slaked lime solution, and a fluidized slaked lime layer height-control device (5) disposed within the tank above the stirring blade, subsequently introducing a predetermined amount of slaked lime into the tank, feeding water, with low-speed stirring, to the tank from the water supply piping in such a rate that the water in the cylindrical or rectangular upper part of the tank ascends at a rate of from 0.25 to 1.2 mm/sec, and taking out an aqueous solution of slaked lime from the tank through the effluent piping.