Method for separating non-metal material

The present invention discloses a method for linearly separating a non-metal material such as a glass substrate of large width. A glass substrate (2) is mounted and fixed on a supporting stand (1), a sheath heater (3) is disposed in contacting with a bottom surface of the glass substrate (2) to form a heating zone (2a), whereby a crack (5) is started to be extended from an end face flaw (4) formed at an edge (6) of the glass substrate (2) in advance. A tip of the crack (5) is cooled locally by spraying air from a nozzle (9) movably disposed on a top surface of the glass substrate (2) to further extend the crack (5) and the nozzle (9) is moved to the end of the glass substrate (2) to separate the glass substrate (2).