There is a few article reported about ratchet syndrome. We report a case of ratchet syndrome caused by its small hair-pin curve of lead triggered to retract the lead itself. A 69 years old man with a past history of inferior wall myocardial infarction, presented with progressive congestive heart failure. He underwent implantation of CRTD in our hospital. On 33 days after implantation, the shock lead dislodgement was revealed. X-ray showed that the lead tip was in left subclavian vein leaving its screw out, and a large part of proximal portion of the lead was retracted into the pocket, while the other two leads were remained in appropriate position and the device had not rotated. X-rays series showed that the hair-pin curve had been expanding gradually from just after implantation. Relatively stiff shock lead which was bent strongly expanded the curve in the pocket and ratchet-like movement occurred in this case. We report a new type of ratchet syndrome.