Callus distraction (callotasis) has already become a popular procedure in the lengthening of limbs. With the development of a small device, it can also be applied to the hand or foot, thus providing benefits in the treatment of brachymetatarsia. Four toes of 3 patients with brachymetatarsia of the fourth toe were treated by this method, and excellent elongation of from 17.50 to 32.55 mm (average, 23.71 mm) was acquired. The treatment period ranged from 78 to 141 days (average, 112.5 days). More time was required in the earlier cases, but the most recent took only 11 weeks. The optimal distraction rate is considered to be 0.35 mm per half-day. Reshortening after treatment ranged from 3.6 to 5.5 mm (average, 4.7 mm), or from 15% to 26% (average, 20.5%) of the distracted length. About 90% of the resorption was observed within 1 month, except in a case that involved a postoperative fracture, and no resorption was seen after 2 surgical months. Regarding complications, subluxation of joints was seen in 2 patients and a postoperative fracture in 1 patient. Subluxation was caused by tendons resisting elongation. The procedure is described, representative cases are illustrated, and problems encountered are discussed.