This paper describes supporting software which permits the facile utilization of the M345 colored-character display unit which is connected to the MELCOM 9100/30F in our department. The basic software which the computer maker has provided us enables us to utilize M345 only when programs are written in assembly language. Programming in this language is rather troublesome job. Thus we designed and built supporting software which enables us to write programs in FORTRAN utilizing M345 directly and to command it in job control language. This supporting software aims primarily at facilitating conversational operation utilizing the M345. Secondary aim is the simplification of operations such as input and output of data, file editing, and console operation through the M345.