Provided is a novel cancer treatment method using an FGFR inhibitor that exhibits a very good antitumor effect and little adverse effect. Also provided are a combination preparation for treating malignant tumors that contains a compound represented by general formula (I) or a pharmaceutically acceptable salt thereof and one or a plurality of other compounds having an antitumor effect or pharmaceutically acceptable salts thereof； and a pharmaceutical composition that contains both agents. The following are also provided: an antitumor effect potentiator, an antitumor agent, a kit for treating malignant tumors, etc. that contain the compound represented by general formula (I) or a pharmaceutically acceptable salt thereof.本發明提供一種使用表現出顯著優異之抗腫瘤效果且副作用較少之FGFR抑制劑之新穎癌症治療方法。 本發明提供一種包含通式(I)所表示之化合物或其藥學上所容許之鹽、及1種或複數種其他具有抗腫瘤效果之化合物或其藥學上所容許之鹽之用於惡性腫瘤治療之組合製劑、及包含兩劑之醫藥組合物。又，本發明提供一種包含通式(I)所表示之化合物或其藥學上所容許之鹽之抗腫瘤效果增強劑、抗腫瘤劑、惡性腫瘤治療用套組等。
