In this report, a 69-year-old man with fever, thrombocytopenia, and hepatic and renal dysfunction presented to our hospital. His disease progression was rapid, and he became unconscious. The patient was diagnosed with severe fever with thrombocytopenia syndrome (SFTS). However, his inflammation markers continued to rise until a mixed fungal infection was detected. Metagenomic next-generation sequencing of blood detected elevated sequence numbers for Actinomucor elegans and Aspergillus fumigatus. The culture of the bronchoalveolar lavage fluid were positive for Aspergillus fumigatus and Escherichia coli. Infection was controlled after adjusting the antifungal regimens against Actinomucor elegans. The patient's condition gradually improved. This patient was diagnosed with possible mucormycosis. Reports of Mucorales infection associated with SFTS are rare. We hope that this case report will draw the attention of physicians in the area where SFTS occurs to figure out if patients with SFTS are susceptible to mucormycosis.