1. A method of inspecting an apparatus for processing a sheet, which has an insert section which inserts the sheet, a conveying section which conveys the sheet inserted into the insert section, a detecting section which detects features from the sheet conveyed by the conveying section, and an inspection section which inspects the sheet based on the features detected by the detecting section, comprising: conveying a medium by the conveying section; detecting features from the medium by the detecting section when the medium having the features formed in a predetermined pattern is inserted into the insert section; judging a condition of the apparatus based on the features detected by the detecting section from a medium conveyed by the conveying section; and giving information on the judgment result based on the judgment.