This case report demonstrated the usefulness of scoring balloon when luminal narrowing occurred after balloon angioplasty in the left circumflex artery due to coronary intramural hematoma. Although a stent was placed, coronary flow was not improved. We intended to make a fenestra between the true lumen and the hematoma using a scoring balloon (Scoreflex® 2.0 × 10 mm, OrbusNeich, Tokyo, Japan) which was dilated in the distal segment of the branch. Angiograms showed restoration of TIMI-3 flow with a long dissection spanning from distal of the stent to the scored area. After 3 months and 1 year, follow-up coronary angiograms demonstrated occluded false lumen and good coronary flow in the treated vessel.