To enable a stamping part to stamp in an appropriate part of a document when one or both sides of the document are read.

The automatic document feeder comprises a conveyance path HR and a stamping part 73. In the conveyance path HR, a document is transported in one direction from a paper supply port 8a to a paper ejection port 8b. In the conveyance path, the stamping part 73 stamps a document in a position downstream of a document reading position P2 after one side or both sides of the document is read.