It is necessary to distinguish between pyogenic and tuberculous spondylitis of infectious spondylitis, if it is pyogenic spondylitis, antimicrobial therapy should be directed against an identified microorganism and clinical assessment should be done at 4 weeks. But if microorganism is a anaerobic bacteria, especially Peptostreptococcus anaerobius, combination antibiotic therapy should be considered bacause it may be a component of mixed infections as a passenger and have abilities to induce abscesses, other bacterial growth as a synergy effect. In addition, echocardiography may be necessary because pyogenic spondylitis is associated with infective endocarditis about 12%. We report a 64-year-old man who was treated for infectious spondylitis accompanied by Peptostreptococcus anaerobius bacteremia, but had to undergo heart surgery because an attack of infective endocarditis with systemic embolism during hospitalization.