It is an object of the present invention to provide a stable solid preparation comprising a 4,5-epoxymorphinan derivative or a pharmacologically acceptable acid addition salt thereof as an effective ingredient. That is, the present invention provides the stable solid preparation comprising the 4,5-epoxymorphinan derivative or the pharmacologically acceptable acid addition salt thereof as the effective ingredient, and comprising sodium thiosulfate, a sugar or a sugar alcohol and hydroxypropylcellulose having a low degree of substitution in an amount of 1 to 30% by weight per weight of a unit containing the effective ingredient.
