An object is to provide a hydromorphone hydrochloride- or oxycodone hydrochloride hydrate-containing sustained-release pharmaceutical composition for oral administration that reliably exhibits its main pharmacological effect and has excellent formulation stability that avoids dose dumping of the principal drug, such as alcohol resistance. The present invention provides a sustained-release pharmaceutical composition comprising (A) hydromorphone hydrochloride or oxycodone hydrochloride hydrate, (B) hydroxypropyl methylcellulose acetate succinate having a median size (D 50 ) of 40 µm or smaller, (C) hydroxypropyl cellulose, and (D) a saccharide, wherein the content ratio of the component (C) to the component (B) by weight in the composition, (C)/(B), is 11/3 to 3/11.
