Provided is a controlled-release preparation administered orally once a day that exhibits an optimum pharmacological clinical effect, prepared in the form of a bilayered tablet, a dual tablet, or a multilayered tablet including an immediate-release layer containing aceclofenac, a water-soluble additive, an insoluble additive, a solubilizer, a disintegrating agent and a filler, and a slow-release layer containing aceclofenac, a slow-release base, a disintegrating agent, a binder, a filler, a fluidizer, a solubilizer, and a lubricant.
