To provide the housing system of a file, which consists of detachable cassettes so as to freely decrease and increase the thickness and housing capacity of documents in the file and, at the same time, binding systems of documents or the like, which are different from one another, can be mixedly present in one file.

In a file for housing documents or the like, by comprising binding means of the documents and means of detaching from attaching to the file, binding systems, which are different from one another, can be mixedly present in one file and, at the same time, the thickness and housing capacity of the file can be made variable.