This study performed an economic analysis for no-till practice of paddy rice compared with traditional till practice of paddy rice. The effect of reducing greenhouse gas (GHG) emissions from soil and agricultural machinery was added to economic outcome of no-till practice. Experimental data of GHG and yield by practices were obtained from National Institute of Crop Science and partial budgeting method was adopted for the analysis. Results showed that GHG reduction from no-till practice was very large in soil compared with agricultural machinery. The economic outcome of no-till practice was larger than that of traditional till practice even when it did not contain GHG reduction effect. In addition, no-till practice showed positive economic performance regardless of the ownership for agricultural machinery. The results of this study are expected to be highly useful as legitimacy of policy support for no-till paddy rice practice.