Abstract] [Problem] 5 Provided is a compound which is useful as an active ingredient of a pharmaceutical composition for treating lung cancer. [Means for Solution] The present inventors have studied a compound useful as an active ingredient of a pharmaceutical composition for treating lung cancer, and as a result, it was found that a 10 quinazoline compound has an excellent G12C mutation KRAS inhibitory activity, and which can be used as a therapeutic agent for lung cancer, and thereby the present invention has been completed. The quinazoline compound of the present invention and a salt thereof may be used as the therapeutic agent for lung cancer. [Selected Figure] Nil
