A process for producing an oral preparation containing a first water-swellable gel-forming layer and a second water-swellable gel-forming layer as outermost layers, a medicine being sealed in an inner space formed by bonding the periphery of the first water-swellable gel-forming layer and the periphery of the second water-swellable gel-forming layer either directly or via an adhesive layer, the process including (a) a step of forming a first water-swellable gel-forming layer, (b) a step of forming a recess in a predetermined area of the first water-swellable gel-forming layer, (c) a step of filling the recess with a medicine to obtain a medicine-containing body, and (d) a step of forming a second water-swellable gel-forming layer over the medicine-containing body directly or via an adhesive layer so that the first water-swellable gel-forming layer and the second water-swellable gel-forming layer are bonded around the recess, and a process for continuously producing the oral preparation are disclosed. According to the above process for producing an oral preparation, an oral preparation in which the medicine is completely masked so that the medicine can be administered without a problem of bitterness and odor of the medicine can be efficiently produced without causing the medicine to deteriorate due to heat history, without a loss of the medicine, and without a limitation to the amount of the medicine to be added.