Invasive pulmonary aspergillosis (IPA) is rarely reported in patients who have normal immune function. Recently, IPA risk was reported in nonimmunocompromised hosts, such as patients with chronic obstructive pulmonary disease and critically ill patients in intensive care units. Moreover, influenza infection is also believed to be associated with IPA among immunocompetent patients. However, most reports on IPA with influenza A infection, including pandemic influenza H1N1, and IPA associated with influenza B infection were scarcely reported. Here, we report probable IPA with a fatal clinical course in an immunocompetent patient with influenza B infection. We demonstrate IPA as a possible complication in immunocompetent patients with influenza B infection. Early clinical suspicion of IPA and timely antifungal therapy are required for better outcomes in such cases.