A calibrating and positioning structure of a scanning apparatus is provided. The scanning apparatus includes a scanning platform and a scanning window. The scanning window has a wide edge. The calibrating and positioning structure includes a calibrating part and at least one positioning part. The calibrating part is disposed on the scanning platform, and aligned with the wide edge of the scanning window. The at least one positioning part is partially overlapped with the calibrating part, wherein the positioning part is not aligned with the wide edge of the scanning window.