PURPOSE: To acquire the detailed execution information on a program and to improve the operability and the maintenance properties of a program state display device by displaying the program state on a terminal, through a screen information display mechanism.

CONSTITUTION: An operator of a terminal 2 wants to know the state of a program carried out at a terminal 1 while a program 3 containing the screen information 4 is carried out at the terminal 1. Under such conditions, a screen information copying mechanism 5 is driven by the terminal 2 via e control line 12. Then the mechanism 5 calls out a program screen information storing part 4 through a control line 13 and copies the screen information 21 to a screen information storage mechanism 6 controlled via a control line 14. Thus the screen information on the terminal 1 is stored in the mechanism 6. These stored data 15 are displayed as the data 16 on the terminal 2 by a screen information display mechanism 7. Thus the screen of the terminal 1 is displayed on a display device screen of the terminal 2. As a result, the program executing state is not shown just in a mere status and a screen itself can be shown.