A composite microparticle manufacturing method includes: a step of preparing a first selective element-containing raw material and a second selective element-containing raw material, the first selective element-containing raw material containing one or more first selective elements selected from a copper element, a molybdenum element, and a silver element, the second selective element-containing raw material containing one or more second selective elements selected from titanium, germanium, silicon, tin, aluminum, zinc, zirconium, hafnium, iron, yttrium, niobium, tantalum, calcium, magnesium, indium, tungsten, molybdenum, and nickel; and a composite microparticle generation step of introducing both of the prepared raw materials into thermal plasma, evaporating the raw materials, and cooling the evaporated raw materials to generate composite microparticles including base particles and first selective element-containing microparticles being present on surfaces of the base particles, the base particles having an average particle diameter of from 10 nm to 300 nm inclusive.