Recently, mycelium-based composites are attracting attention as eco-friendly materials to replace fossil fuel-based plastics and Styrofoam. Various cellulose-based substrates are used as culture substrates for various mycelium materials. This study was conducted to evaluate the possibility of using various agricultural by-products as mycelium material substrates that can replace the main material, oak sawdust. The growth of mycelia was confirmed by inoculating the culture substrate with Irpex lacqueratus (KMCC02967) with four types of agricultural by-products (peach branch hemp stem, perilla stem, and pepper stem). As a result, compared to the oak sawdust substrate, when not only the agricultural by-products substrate itself but also nutritional sources such as rice and wheat bran were added, the effect of promoting mycelia growth was confirmed. The results of this study clearly show the potential of agricultural by-products to shorten the growth period of mycelia by replacing existing oak sawdust and reduce production costs through this. Based on these research results, it is suggested that agricultural by-products can be used as high value-added industrial materials and further suggests that they are sustainable alternatives that can contribute to carbon reduction and building a resource circulation economy.