Background Miliary pulmonary metastasis characterized by tiny nodules is a rare metastatic pattern in advanced non-small cell lung cancer (NSCLC) and is usually seen in patients harboring an EGFR mutation, and amylase-producing lung cancer is highly uncommon and rarely reported in NSCLC patients who have an EGFR mutation. Case A 32-year-old Japanese female was found to have miliary pulmonary nodules throughout both lung fields on a chest x-ray examination during an annual health check-up. Further examination by computed tomography (CT) revealed diffuse, bilateral, miliary nodules. Blood tests showed no increased tumor marker levels, but there was a significantly increased serum amylase level. A diagnosis of ALK-rearranged adenocarcinoma was made based on the results of a mediastinal lymph node biopsy obtained by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). Treatment with alectinib resulted in rapid regression of the CT shadows and a reduction in the patient's serum amylase level. Conclusion We have reported a case of ALK-rearranged NSCLC with a miliary pulmonary metastasis pattern that was sensitive to alectinib and in which the serum amylase level decreased in response to treatment with alectinib. Young patients with miliary pulmonary metastasis should be checked for all driver mutations.