Provided is a novel bacteriophage ΦCJ23 (KCCM11365P). In addition, the present invention relates to an antibacterial composition including the bacteriophage ΦCJ23 (KCCM11365P) as an active ingredient. Further, provided is a method of preventing and/or treating infectious diseases by avian pathogenic Escherichia coli (APEC) in birds using the bacteriophage ΦCJ23(KCCM11365P) or the antibacterial composition containing the bacteriophage ΦCJ23(KCCM11365P) as an active ingredient.