1. A writing apparatus to which an external writing unit is connected, comprising: a writing unit configured to write, to a write object provided to a conveyed item conveyed in a conveying direction, at least identification information that identifies the write object; a first reading unit provided in more downstream side in a conveying direction than the writing unit and configured to read identification information from the write object; a determination unit configured to determine whether or not the identification information written to the write object and read by the first reading unit is consistent with identification information having to be written to the write object; and a notification unit configured to, when the determination unit determines that identification information written to a first write object being the write object and read by the first reading unit is inconsistent with the identification information having to be written to the first write object, notify the external writing unit of recovery information including at least one of identification information having to be written to the first write object and a write content corresponding to the identification information having to be written to the first write object.