Abstract: A brittle plate processing method includes having a first portion of a brittle plate supported flat on a flat part of a support member that supports a first surface of the brittle plate, pressing a cutter against a second surface of the brittle plate opposite to the first surface, and forming a scribe line in the second surface of the brittle plate by moving the cutter and the support member relative to each other. In pressing the cutter, the cutter is pressed to a predetermined position on a second portion of the brittle plate other than the first portion. When the cutter is pressed to the predetermined position on the second portion of the brittle plate, the shape of the brittle plate due to bending deformation is defined by a defining part of the support member.