The present invention relates to a novel bacteriophage ΦCJ25 (KCCM11463P) and a composition comprising the same as an active ingredient. In addition, the present invention relates to a method for preventing and/or treating infectious diseases caused by avian pathogenic Escherichia coli (APEC) of birds by using the bacteriophage ΦCJ25 (KCCM11463P) or the composition.