A substrate cleaning apparatus includes: a pure water supply line provided with a pure water flow regulator and a pure water supply valve; chemical supply lines each provided with a chemical flow regulator and a chemical supply valve; a merging line where pure water and a plurality of liquid chemicals meet to form a cleaning liquid; a cleaning liquid supply line configured to supply the cleaning liquid to a substrate; and a controller configured to control the pure water flow regulator, the pure water supply valve, the chemical flow regulators, and the chemical supply valves such that the pure water and the plurality of liquid chemicals are present at a predetermined ratio at a meeting point.