Introduction. Several reports state that negative pressure wound therapy (NPWT) with instillation and dwell time (NPWTi-d) is useful in the management of intractable ulcers. However, reports comparing the effects of NPWT and NPWTi-d in the same patient are lacking. Case Report. A 76-year-old man with intractable skin ulcers on both lateral malleoli presented to an outpatient clinic. Conservative treatment over a 3-month period had not been effective. The authors applied NPWT to the left leg and NPWTi-d to the right leg with fibular osteomyelitis to encourage granulation for 28 days. Thereafter, they covered both ulcers with split-thickness skin grafts. Negative pressure wound therapy was applied to the both legs for 1 week postoperatively. During periods in which NPWT and NPWTi-d were utilized, the patient received intravenous cefazolin sodium (1 g twice daily), lasting 7 days after skin grafting. Epithelization was completed in the NPWTi-d-treated ulcer in about 3 weeks and in the NPWT-treated ulcer in about 8 weeks due to the difficulty in healing his residual ulcers. In terms of the efficacy of granulation and debridement of infected granulation tissue, NPWTi-d demonstrated better results with increments in the washing amount. Also, NPWTi-d proved superior in terms of the survival status of the skin graft, the time until the residual ulcer disappeared, and the removal of latent bacteria. Conclusions. From this case report, the authors believe NPWTi-d may be more effective in cases with intractable ulcers associated with infection that need better granulation.