Varicella is a common vaccine-preventable disease that typically affects children aged 2-8 years and usually has a benign outcome. However, varicella infection in adults may cause serious complications, including varicella pneumonia. We report a case of varicella pneumonia in an immunocompetent, unvaccinated man in Japan. A 50-year-old Egyptian man who had been living in Japan for 20 years was brought to the hospital with a 3-day history of fever and a 2-day history of rash and dyspnea. Chest computed tomography revealed an 8-mm-long nodule with a halo in the right S3 segment and mild ground-glass opacities in both lungs. A final diagnosis was made based on identification of varicella-zoster virus via positive immunochromatographic test and polymerase chain reaction from a blister fluid. The patient's pneumonia had improved with acyclovir for 10 days. In Japan routine varicella vaccination in childhood (at ages 12 and 18 months) was introduced in 2014. However, in Egypt, where the patient spent his childhood, varicella vaccine is still not designated as a routine vaccination. The introduction of universal varicella vaccination in more countries and an increase in vaccination coverage are essential to reduce the number of cases of varicella infection, including varicella pneumonia.