Buerger disease is a rare disease of unknown etiology and cannot be treated by bypass surgery or percutaneous re-endovascularization. Although the need for effective limb ischemia prevention strategies is increasingly being recognized, effective preventative strategies are insufficient. The aim of this study using a new pulsed ultrasound device, SX-1001, is to determine whether treatment using SX-1001 can mitigate rest pain and improve blood supply to ischemic legs in patients with Buerger disease. This study is a multicenter, double-blinded, parallel randomized clinical trial testing the efficacy and safety of SX-1001. Treatment using SX-1001 is expected to result in reduction of the visual analog scale score for pain in Buerger disease patients who have Fontaine stage III. A total of 44 patients from 20 hospitals in Japan will be enrolled. The primary endpoint of the trial is a change in rest pain intensity on the visual analog scale score from baseline to 24 weeks. This trial will be the first to show the safety and efficacy of low-intensity pulsed ultrasound using SX-1001 for clinical symptoms in patients with Buerger disease. Low-intensity pulsed ultrasound may be a new therapy for limb ischemia. Ethical approval has been obtained from each of the participating institutes. Study findings will be disseminated through peer-reviewed journals and at scientific conferences.This study is registered at UMIN Clinical Trial Registry (UMIN000014757).