The Annual sales of Japan’s used auto parts are approximately 100 billion yen. Reusing auto parts also significantly contribute to CO2 reduction in the automotive manufacturing industry. However, the coronavirus disease 2019 (COVID-19) pandemic has led to a sharp increase in demand for used vehicles due to delays in delivering new vehicles. Demand for older used and end-of-life vehicles (ELVs) is increasing to compensate for the short supply of new vehicles. This situation poses a challenge to the used automobile parts industry. Specifically, because there is a shortage of ELV supply, the source of auto-used parts is necessary for production. On the other hand, the production rate of a Japanese used automobile parts company depends largely on the parts selection made subjectively by experience of skilled workers. As the current inventory-to-order ratio does not reflect the efficiency of this approach, we analyzed three years of Japan’s nationwide order, sales, and inventory and distribution from Japan’s largest automobile used parts industry network. The objective of this analysis is to identify parameters that may increase the utilization rate of used parts. By performing a supply–demand balance assessment, we found that more than 80% of the products of the top 10 annual order volume were below 50% inventory. We confirmed that the three key parameters to be considered when selecting parts for reuse that should be considered to increase utilization rate are: (1) data-informed selection of popular car models, (2) matching supply and demand information, and (3) improving the product inventory ratio.