This invention provides a suspension for oral administration comprising particles containing amorphous tolvaptan that can inhibit or delay crystallization of amorphous tolvaptan over time in the suspension, and stably maintain high solubility of tolvaptan and excellent absorbability of tolvaptan from the gastrointestinal tract; and a solid formulation for oral administration that can be suspended to prepare the suspension for oral administration at the time of use. This invention relates to a suspension for oral administration, in particular, a syrup, comprising (a) particles containing amorphous tolvaptan, (b) hydroxypropyl methylcellulose (HPMC), and (c) a solvent, wherein the amount of the HPMC (b) is 0.1 to 25% by weight based on the total weight of the suspension for oral administration.