Kirschner wire (K-wire) has been widely used for treatment of fracture for its cost-effectiveness and reliability. This case presents the K-wire breakage in distal interphalangeal joint (DIPJ) fixation. A 55-year-old male patient was injured by a knife and showed rupture of extensor tendon at 1/2 of middle phalanx. A 0.9-mm K-wire was implemented for DIPJ extension, and tenorrhaphy was done. After 6 weeks, we detected breakage of K-wire in the follow-up X-ray. The broken K-wire in the distal phalanx was removed. We removed the remaining K-wire through an incision on volar side of middle phalanx under C-arm after 2 weeks for the patient’s personal reasons. Breakage during postoperative K-wire maintenance is exceedingly rare. This patient is presumed to have ruptured because he continued using his finger. Therefore, while K-wire is present, continued use of finger without protection may cause breakage, so protective measures such as splint are required.