A device for forming a separation starting point that allows separation of a surface layer of a processed member to form a remaining portion is provided. A manufacturing device of a stack including a support and a remaining portion of a processed member whose surface layer is separated is provided. The device for forming the separation starting point includes a stage that supports the processed member, a cutter that faces the stage, a head portion that supports the cutter, an arm portion that supports the head portion, and a moving mechanism that relatively moves the cutter to the stage.