A semiconductor substrate cleaning method includes cleaning a semiconductor substrate formed with a line-and-space pattern, rinsing the substrate, supplying the rinse water to rinse the substrate, and drying the substrate. The rinsing includes supplying deionized water and hydrochloric acid into a mixing section to mix the deionized water and the hydrochloric acid into a mixture, heating the mixture in the mixing section by a heater, detecting a pH value and a temperature of the mixture by a pH sensor and a temperature sensor respectively, adjusting an amount of hydrochloric acid supplied into the mixing section so that the rinse water has a predetermined pH value indicative of acidity, and energizing or de-energizing the heater so that the temperature of the mixture detected by the temperature sensor reaches a predetermined temperature, thereby producing the rinse water which has a temperature of not less than 70° C. and is acidic.