Two patients, a 60-year-old man and 43-year-old woman, presented to our hospital with symptoms of respiratory tract infection. These patients showed imaging findings of multiple small nodules, ground-glass opacities, and consolidations. In case 1, although antibiotics were started, bilateral shadows spread widely, which made us suspect interstitial pneumonia. The condition improved after steroid administration, and there has been no recurrence since completing this treatment. In case 2, the patient recovered rapidly with antibiotics only. In both cases, we performed bronchoalveolar lavage, in which only human rhinovirus infection was detected by multiplex polymerase chain reaction testing, and primary rhinovirus pneumonia was diagnosed.