Cleaning liquid and cleaning method

A cleaning liquid which comprises at least one selected from potassium hydroxide or sodium hydroxide in an amount of 0.01 to 10% by weight, water-soluble organic solvent in an amount of 5 to 80% by weight, a corrosion inhibitor at least one selected from the group consisting of group IX metal of the Periodic Table, group IX metal alloy and group XI metal of the Periodic Table in an amount of 0.0001% by weight and water. The present provides a cleaning liquid and a cleaning method both capable of removing photoresists or its deposits and attached articles on the surface of treated substances such as organosiloxane-based anti-reflection film, configuration protective coat or so without corroding the treated substances, particularly low dielectric constant film, group IX metals of the Periodic Table and their alloy, and group XI metals of the Periodic Table.