The present invention addresses the problem of improving elution property and absorption property from an agent of (S)-1-(3-(4-amino-3-((3,5-dimethoxyphenyl)ethyl)-1H-pyrazolo[3,4-d]pyrimidin-1-yl-1-pyrrolidinyl)-2-propene-1-one which is effective as an anti-tumor agent. Provided is a pharmaceutical composition containing (S)-1-(3-(4-amino-3-((3,5-dimethoxyphenyl)ethyl)-1H-pyrazolo[3,4-d]pyrimidin-1-yl-1-pyrrolidinyl)-2-propene-1-one in combination with a C10-C18 alkyl group-containing sodium alkyl sulfate, particularly a sodium lauryl sulfate.
