A 42-year-old man presented at our emergency department with fever, sputum, and dyspnea. His chest X-ray films showed ground-glass opacities mainly in the upper and middle lung fields. We diagnosed pneumonia, gave antibiotic treatment, and his symptoms improved. However he later showed eosinophilia. We performed additional workup, and diagnosed Toxocara canis larva migrans. We treated him with albendazole for four weeks, but his eosinophil count rose again from the end of treatment one month later. Therefore we performed additional treatment with albendazole for 8 weeks, after which the clinical imaging findings and serum antibody titer improved. There are few reports about additional treatment for Toxocara canis larva migrans, and there is not yet a consensus. We think that we should consider additional treatment in cases that do not show improvement on initial treatment.