Plate glass manufacturing method and manufacturing device thereof

For a sheet glass (G) having an effective region (G1) and an ear portion (Ge) thicker than the effective region (G1) and formed in an unwanted region (G2) at an end portion in a width direction, a scribe line (S) is formed on a surface (Ga, Gy) side of a boundary portion between the effective region (G1) and the unwanted region (G2), and the scribe line (S) is formed in a state in which the sheet glass (G) is suspended and supported in a vertical posture. While the unnecessary area (G2) is pulled in the vertical direction, the plate glass (G) is broken along the scribing line (S). 针对具有有效区域(G1)以及板厚比有效区域(G1)厚的耳部(Ge)形成于宽度方向端部的不需要区域(G2)的板玻璃(G)，在有效区域(G1)与不需要区域(G2)的边界部的表面(Ga、Gy)侧形成刻划线(S)，在将板玻璃(G)以纵姿态悬吊支承着的状态下，在将不需要区域(G2)沿上下方向拉拽的同时将该板玻璃(G)沿着刻划线(S)折断。