Compared to rotational atherectomy (RA), orbital atherectomy (OA) has been shown to decrease procedure failure and reintervention rates in the treatment of severely calcified coronary artery lesions. Our objective was to explore the cost-effectiveness of OA compared to RA in the Japanese healthcare system. A decision-analytic model calculated reintervention rates and consequent total 1-year costs. Effectiveness inputs were therapy-specific target lesion revascularization (TLR) rates and all-cause mortality, pooled from clinical studies. Index and reintervention costs were determined based on claims data analysis of n = 33,628 subjects treated in 2014-2016. We computed incremental cost-effectiveness in Japanese Yen (JPY) per life year (LY) gained based on differences in 1-year cost and projected long-term survival, assuming OA device cost between JPY 350,000 and JPY 550,000. OA was found to be associated with improved clinical outcomes (12-month TLR rate 5.0 vs. 15.7%) and projected survival gain (8.34 vs. 8.16 LYs (+0.17), based on 1-year mortality of 5.5 vs. 6.8%). Total 1-year costs were lower for device cost of JPY 430,000 or less, and reached a maximum ICER of JPY 753,445 per LY at the highest assumed device cost, making OA dominant or cost-effective across the tested range, at ICERs substantially below the willingness-to-pay threshold. In conclusion, orbital atherectomy for the treatment of severely calcified coronary artery lesions, compared to rotational atherectomy, is a cost-effective treatment approach in the Japanese healthcare system due to improved clinical performance.