We report a case of a 58-year-old man suffering from advanced colon cancer with liver metastases. After the sigmoidectomy and left lateral segmentectomy, mFOLFOX6+bevacizumab was initiated. The mFOLFOX6+bevacizumab therapy was performed for 15 courses, but it was stopped because of an increase in serum levels of tumor markers(CEA and CA19-9). For the next treatment, FOLFIRI+panitumumab therapy was performed. At the beginning of the second course, he suffered from dyspnea. Computed tomography showed ground-glass opacities and traction bronchiectasis in both lung fields. He was diagnosed with interstitial pneumonitis induced by irinotecan or panitumumab. Corticosteroid therapy consisting of methyl- prednisolone(1 g/day)administered for three days was significantly effective for treating respiratory failure. Two courses of the therapy were performed, and he was discharged without aftereffects. As with other EGFR tyrosine kinase inhibitors, the frequency of interstitial pneumonitis induced by irinotecan in Japan may increase to European and American levels.