The present invention relates to a novel bacteriophage ¦CJ25 (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 ¦CJ25 (KCCM11463P) or the composition.