A cleaning device for cleaning a mixing vaporizer is provided. The mixing vaporizer includes a first hole that a raw material flows in therethrough, a second hole that carrier gas flows in therethrough, a mixing space that generates mixed gas by mixing the raw material and the carrier gas, a carrier gas nozzle that is connected to the second hole for supplying the carrier gas to the mixing space, and a third hole that discharges the mixed gas. The cleaning device cleans the mixing vaporizer by circulating a cleaning solution through at least one the first hole, the second hole, and the third hole.