Process for producing glass plate, and glass plate

This process for producing a glass plate is a process for producing a glass plate having a modified surface and includes a gas-contacting step in which hydrogen fluoride (HF) gas, hydrogen chloride (HCl) gas, and water vapor are brought into contact with one and/or both of the main surfaces of the glass plate. In the gases including hydrogen fluoride (HF) gas which are to be used in the gas-contacting step, the volume ratio of the water vapor to the hydrogen fluoride (HF) gas, water vapor/HF gas, is 8 or higher.