The invention provides is a novel compound having an EGFR inhibition activity and also having a cell proliferation inhibition effect. Also provided is a medicinal agent which has an EGFR inhibition activity and is therefore useful for the prevention and/or treatment of cancer. A compound represented by general formula (I) or a salt thereof.本發明之課題在於提供一種具有EGFR抑制作用且具有細胞增殖抑制效果之新穎化合物。此外,提供一種基於EGFR抑制作用而對預防及/或治療癌症有用之藥品。本發明之解決手段即是下述通式(I)所示之化合物或其鹽。