The mechanisms underlying anaplastic lymphoma kinase (ALK) resistance have not been well investigated in clinical practice. We herein report the case of a lung cancer patient with carcinomatous meningitis who had an ALK I1171T resistance mutation revealed by direct DNA sequencing of the cerebrospinal fluid after treatment with cytotoxic chemotherapy, crizotinib, and alectinib. I1171T is considered to be sensitive to ceritinib. Although ceritinib was not effective initially, we chose ceritinib again after whole-brain radiotherapy and ventriculoperitoneal shunting. Although the response duration was short, spinal magnetic resonance imaging revealed a marked response. The identification of an acquired ALK resistance mutation will aid in choosing the optimum sequence therapy.