The purpose of this study was to compare and evaluate the performance and economic of an auto-steering onion transplanter and a conventional transplanter to determine their applicability in actual agricultural environments. Performance evaluation was conducted by analyzing path-tracking accuracy through planting position deviations and measured working time, while economic feasibility was assessed by calculating cumulative operating costs based on field capacity. The results showed that the auto-steering transplanter reduced the maximum and average planting position deviations by 76.2% and 81.7%, respectively, compared to the conventional transplanter, and shortened straight-line and turning operation times by 8.4% and 25.0%, respectively, resulting in a 10.8% improvement in overall field capacity. The economic analysis showed that the cumulative cost of the conventional transplanter was lower for cultivated areas below 4.44 ha, and the auto-steering transplanter was lower for areas above 4.44 ha and based on time, it became more advantageous after approximately 2.52 years of operation for farms with the average onion cultivation area of 1.76 ha. These findings indicate that although the auto-steering transplanter requires a higher initial investment, long-term or large-scale use offsets this cost through accumulated savings from improved operational efficiency, thereby providing economic benefits. This study quantitatively demonstrates the technical performance and economic feasibility of the auto-steering transplanter, offering valuable baseline data for promoting mechanization and reducing labor demand in onion cultivation.