PURPOSE: To decide rapidly and precisely by outputting corresponding process information or a waiting event in accordance with anyone of the state, i.e. an executing state, a waiting state or an operation-enabled state, from a process relating to a monitor request.

CONSTITUTION: When a process state display request command is inputted from a console 31, the inputted command is analyzed and the analyzed result is transferred to a process information acquiring means 22. When the process is in the executing state, the process information is acquired from a process control table 13 and displayed on a CRT 32. When the process is in the waiting state, the process information is transferred to a waiting process information acquiring means 23 and the waiting information is acquired from a process synchronization control means 14 and displayed on the CRT 32. When the specified process is in the operation-enabled state, the means 22 acquires the process information from the table 13 and transfers the process information to a process state means 24. If a specified program is not registered in the table 13, a message informing its unregistration is transferred to a display means.