PURPOSE: To obtain a screen hard copy with simple constitution by forming a hard copying system connecting a signal conversion means to a local area network(LAN) line for mutually connecting plural work stations and utilizing the LAN circuit.

CONSTITUTION: Plural high performance computers (work stations) W1 to W3 are connected to the LAN line 10. Each of the work stations W1 to W3 consists of a computer body 11 and a display 12. A signal conversion means 20 for converting an analog video signal inputted to the display signal input terminal of a display device in each work station into a digital video signal and outputting the converted signal to network adaptors 13, 14 is also included in each work station and the hard copy of a screen displayed on the display device in each work station is outputted from a printer 15 through the LAN line 10. Thus, a screen hard copy can simply be obtained.