To obtain a novel therapeutic drug for a malignant tumor or fibrosis. Used is a compound represented by formula (1), a salt thereof, or a solvate thereof. Also used is a therapeutic drug for a malignant tumor or a therapeutic drug for fibrosis, comprising a compound represented by formula (1), a salt thereof, or a solvate thereof.藉由本發明獲得針對惡性腫瘤或纖維症的新的治療藥。本發明使用式(1)所示的化合物、其鹽或它們的溶劑合物。或使用含有式(1)所示的化合物、其鹽或它們的溶劑合物的惡性腫瘤的治療藥或纖維症的治療藥。