An 83-year-old woman was admitted due to effort related chest squeezing over the duration of 5 months. A coronary angiogram revealed significant in-stent restenosis at proximal left anterior descending artery. Optical coherence tomography (OCT) image acquisition was successfully performed using a non-occlusive technique. Restenotic tissue consisting of eccentric layers was observed by the OCT. The only imaging method of intracoronary evaluation using a 4F guiding catheter is an OCT. An OCT assessment was helpful for the percutaneous coronary intervention using a 4F guiding catheter.