A method for cutting apart a glass substrate is provided whereby scribing of the glass substrate is possible without being affected by the presence or thickness of a deposited film formed thereon and without scratching the deposited film. To treat a glass substrate having a deposited film, such as a thin film or resin film, formed on one surface thereof, there are provided a shaving device, which is a blade that removes strip-shaped portions of the deposited film to expose strip-shaped regions on the glass substrate, and a wheel cutter that forms scribed lines along the strip-shaped regions exposed on the glass substrate. The glass substrate is cut apart along the scribed lines.