The purpose of the present invention is to provide a method for predicting the effectiveness of an angiogenesis inhibitor in a subject suffering from a tumor. Provided is a method comprising a step of testing for the presence or absence of an a mutation or loss of expression of B-Raf and PTEN in a sample of tumor tissue from the subject. By using the presence or absence of or a mutation or loss of expression of B-Raf and PTEN as an indicator, this method enables the antitumor effectiveness of the angiogenesis inhibitor to be predicted without administering the angiogenesis inhibitor to the subject.