The formulation for oral administration of the present invention containing Mosapride or its salt is a double layer formulation consisting of a fast-release layer for rapid release of a drug and a sustained-release layer for slow release in order to simultaneously satisfy the rapid exhibition of pharmacological activities and sustained maintenance of pharmacological activities for 24 hours, wherein the high-viscosity hydroxypropyl methylcellulose (HPMC) and the low-viscosity HPMC are used in mixture such that the content of a high viscosity HPMC as a controlled-release matrix within the sustained-release layer has a higher content, thereby capable of controlling the dissolution rate in the regions having different pH values within the gastrointestinal tract and/or the retention time in the gastrointestinal tract. Additionally, the formulation of the present invention is a small-sized preparation with a total weight of 200 mg or less, preferably from 150 mg to 160 mg, thus capable of improving drug compliance of patients.