PURPOSE: To stop only the terminal which registers a transaction message in a message queue file in the case of overflow of the message queue file in a computer system.

CONSTITUTION: Transaction message from terminals 5l to 5n are distributed to message queue files 21 to 2m by a message distributing means 11 in a host computer 1. A schedule means 3 takes out transaction message from message queue files 21 to 2m and executes application programs 41 to 4x. A message queue file monitor means 12 is started at intervals of a certain time by a timer report means 13 to monitor the number of unprocessed message held in each of message queue files 21 to 2m; and if a message queue file almost overflows, this means 12 reports its message queue file name to a terminal stopping means 14. The terminal stop means 14 reports the terminal stop to terminals which will register message in the message queue file.