Abstract: An apparatus for removing photoresists includes a chamber including a substrate support, configured to support a substrate, and a nozzle unit disposed toward the substrate support, an ozone solution generator configured to generate an ozone solution, an acid solution reservoir configured to store an acid solution, first and second supply lines connected to the ozone solution generator and the acid solution reservoir respectively, and an in-line mixer configured to prepare a photoresist removing solution by mixing the ozone solution supplied from the first supply line, and the acid solution supplied from the second supply line, and supply the photoresist removing solution to the nozzle unit.