The infection caused by non-b-type Haemophilus influenzae has been increasing in this Hib (H. influenzae serotype b) vaccination era. H. influenzae serotype f (Hif) is considered as one of those emerging pathogens. In general, H. influenzae is a common pathogen of such as pneumonia, otitis media, and meningitis, but is rare in soft tissue infection, especially at the extremity. We report a rare case of severe soft tissue infection caused by Hif which occurred at the lower extremity of immunocompetent adult patient.