PURPOSE: To simplify the operation of a paper feeder for copying machines, while diming at improvement in controllability, by detecting attachment of a standard size storage device and causing paper feeding to be carried out from the standard storage device in accordance with a set preferential order unless otherwise the storage device selected.

CONSTITUTION: A main control unit 401 achieves the readout of codes corresponding to cassettes 105 and 106 upon power supplying. Next, a name corresponding to size B5 of a sheet paper P of the cassette 105 is stored in the RAM area of an address 1A as well as a name corresponding to size A4 of the sheet paper P of the cassette 106 is stored in the RAM area of an address 1B respectively. Then, the number of copying sheets 10 is inputted into a loop waiting for key-in operation by means of, for example, a ten key 116 and a copy button 114 is pressed without any other key input. When the key-in data are stored in the specified area, if this device is not operated by judgment of whether there is a size selection means, the main control unit 401 calls each cassette name out of these addresses 1A and 1B while computes a difference in the contents and if the difference is larger than 0, it sets the address of a RAM407 down to 0 whereby a key 122 is lighted and copying takes place.