Method for producing glass film

A method of manufacturing a glass film, the method comprising:

• a forming step of forming a band-shaped glass film by a forming device;
• and
• a conveying step of conveying the glass film along a lateral conveying direction by a conveying device,
• wherein the conveying step comprises:
• a cutting step of removing an end portion of the glass film in a width direction as a non-product portion;
• and
• a discarding step of discarding the non-product portion,
• wherein, in the discarding step, a scratch is formed on a part of the non-product portion, and the non-product portion is broken with the scratch as a starting point,
• wherein, in the discarding step, a crack formed along a longitudinal direction of the glass film from a distal end portion of the non-product portion formed by breaking the non-product portion is guided by a guiding member to propagate to an outer end portion of the non-product portion in the width direction,
• wherein the guiding member is positioned separated upward from the non-product portion, and
• wherein the guiding member comes into contact with a part of the non-product portion that separates upward from the conveying device when the crack is formed at the distal end portion of the non-product portion so as to direct the crack that propagates from a downstream side toward an upstream side in the lateral conveying direction along the longitudinal direction of the glass film toward the outer end portion of the glass film in the width direction.