A molten glass cutting apparatus, comprising: a pair of shear blades (30, 40); and base portions (50, 70) each provided for a base end part of each of a pair of the shear blades, wherein a pair of the base portions are relatively moved toward each other so that tip parts of a pair of the shear blades overlap, and a shearing force by cutting edges (31a, 41a) of a pair of the shear blades cuts molten glass (Gm) falling from above, each of a pair of the shear blades having projecting portions (32, 42) formed therein on both sides in a width direction and on a cutting edge side, the projecting portions (32, 42) each projecting in a length direction of the shear blade, the projecting portions of each of a pair of the shear blades being inclined in a direction opposite to a side where the tip parts overlap so that each projecting portions serves as a guide when the tip parts of a pair of the shear blades overlap by the relative movement toward each other, characterized by a first support portion (60, 71, 72a, 72b; 60, 90-93) provided at the base end part of one of a pair of the shear blades, the first support portion (60, 71, 72a, 72b; 60, 90-93) supporting the shear blade with respect to the base portion so as to be rotatable around a first axis extending in the width direction of the shear blade; a second support portion (60, 71, 72a, 72b; 60, 90-93) provided at the base end part of one of a pair of the shear blades, the second support portion (60, 71, 72a, 72b; 60, 90-93) supporting the shear blade with respect to the base portion so as to be rotatable around a second axis extending in the length direction of the shear blade; a restriction portion (80a, 80b) that restricts rotation of the shear blade provided with the first support portion around the first axis so that inclined portions of the projecting portions of each of a pair of the shear blades face each other when a pair of the shear blades are separated; and an applying portion (83a, 83b, 175, 183) that applies an elastic force around the first axis for pressing a pair of the shear blades against each other to the shear blade provided with the first support portion. a pair of shear blades (30, 40); and base portions (50, 70) each provided for a base end part of each of a pair of the shear blades, wherein a pair of the base portions are relatively moved toward each other so that tip parts of a pair of the shear blades overlap, and a shearing force by cutting edges (31a, 41a) of a pair of the shear blades cuts molten glass (Gm) falling from above, each of a pair of the shear blades having projecting portions (32, 42) formed therein on both sides in a width direction and on a cutting edge side, the projecting portions (32, 42) each projecting in a length direction of the shear blade, the projecting portions of each of a pair of the shear blades being inclined in a direction opposite to a side where the tip parts overlap so that each projecting portions serves as a guide when the tip parts of a pair of the shear blades overlap by the relative movement toward each other, characterized by a first support portion (60, 71, 72a, 72b; 60, 90-93) provided at the base end part of one of a pair of the shear blades, the first support portion (60, 71, 72a, 72b; 60, 90-93) supporting the shear blade with respect to the base portion so as to be rotatable around a first axis extending in the width direction of the shear blade; a second support portion (60, 71, 72a, 72b; 60, 90-93) provided at the base end part of one of a pair of the shear blades, the second support portion (60, 71, 72a, 72b; 60, 90-93) supporting the shear blade with respect to the base portion so as to be rotatable around a second axis extending in the length direction of the shear blade; a restriction portion (80a, 80b) that restricts rotation of the shear blade provided with the first support portion around the first axis so that inclined portions of the projecting portions of each of a pair of the shear blades face each other when a pair of the shear blades are separated; and an applying portion (83a, 83b, 175, 183) that applies an elastic force around the first axis for pressing a pair of the shear blades against each other to the shear blade provided with the first support portion.