This paper analyzes the transaction network structure among plastic product manufacturing companies in Tsubame City using a dataset that comprehensively captures the transaction relationships in procurement and sales between companies. The degree distribution of the transaction network reveals characteristics of a scale-free network, similar to other inter-company transaction networks. Furthermore, plastic product manufacturing companies in Tsubame City exhibit a diverse set of customers in comparison to suppliers. In procurement, there is a significant number of transactions with wholesale companies, while in sales, transactions with manufacturing companies are more prevalent. This suggests that plastic products in Tsubame City are likely used as input materials in other manufacturing industries.