A mobile communication system requires no fill code in a signal transmitted by way of radio communication between a mobile station and a radio base station. In a radio base station or a mobile station, a base station fill controller or a mobile station fill controller deletes a fill code from a picture signal which has been delivered from a facsimile apparatus connected thereto and which is to be transmitted to another facsimile apparatus through a radio circuit, and a base station fill controller or a mobile station fill controller inserts a fill code into a picture signal transmitted from another facsimile apparatus through the radio circuit such that the scan time of the picture signal is not shorter than the minimum scan line time of the facsimile apparatus connected thereto which is read from a base station terminal ability memory or a mobile station terminal ability memory. The picture signal with the inserted fill code is then delivered to the facsimile apparatus connected thereto.