A 69-year-old woman with lung adenocarcinoma, harboring anaplastic lymphoma kinase (ALK) gene rearrangement, was treated with alectinib as first-line chemotherapy. On the 98th day after initiation of alectinib administration, a chest computed tomography (CT) scan showed diffuse ground glass opacities in both lungs with a clinical manifestation of desaturation. Further examinations led to the diagnosis of alectinib-induced interstitial lung disease (ILD). Her CT scan findings and respiratory condition improved after the discontinuation of alectinib and the initiation of corticosteroid therapy. Progression of the lung adenocarcinoma was detected two months after the discontinuation of alectinib, so cytotoxic chemotherapy was initiated as second-line chemotherapy. However, neither the second- nor third-line chemotherapy showed any clinical benefit for more than two cycles. Lorlatinib was initiated as the fourth-line therapy, and 15 months later there was neither disease progression of lung adenocarcinoma nor recurrence of ILD.