Monochamus alternatus Hope, the Japanese pine sawyer (Coleoptera: Cerambycidae), is a longhorn beetle that is a known vector of the pinewood nematode Bursaphelenchus xylophilus (Steiner et Buhrer) Nickel. Beauveria bassiana (Balsamo) Vuillemin is an entomopathogenic fungus that is widely used as a microbial control agent because of its ease of mass production and safety to most vertebrates. To identify molecular targets that are potentially associated with B. bassiana toxicology, differentially expressed gene (DEG) libraries of M. alternatus contacted with B. bassiana have been prepared. The transcripts are sequenced using the Ion Proton platform; We identify 5,637, 9,181, and 1,787 sequences that involved cellular components, molecular functions, and biological processes, respectively. Fifty DEGs are enriched in the metabolism of xenobiotics by the cytochrome P450 pathway, and 33 DEGs are enriched in insect hormone biosynthesis by a Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis of the DEGs. The pathways associated with these unique candidate targets yield new insights that will lead to an improved understanding of their functions and relationships. Artificial utilization of B. bassiana may be beneficial to the biological control of M. alternatus and other pests.