The present invention relates to a stable tablet comprising a 4,5-epoxymorphinan derivative or a pharmacologically acceptable acid addition saltthereof as an effective ingredient. That is, the tablet according to thepresentinvention comprises: (1) as the effective ingredient, a specific 4,5-epoxymorphinanderivative or a pharmacologically acceptable acid addition salt； (2) sodiumthiosulfate； (3) at least one selected from the group consisting ofsaccharides andsugar alcohols； and (4) crospovidone, sodium carboxymethyl starch or a mixturethereof, in which tablet the content of the aforementioned (4) is 1 to 20% byweightper unit weight containing the aforementioned effective ingredient.
