Display screen sharing system that shares common screen among a plurality of terminals comprises transmission side terminal that has operation right for common screen; and reception side terminal that does not have operation right for common screen. Reception side terminal comprises display area detection unit that acquires display area information indicating area of common screen displayed at reception side terminal itself, and supplies display area information to transmission side terminal. Transmission side terminal comprises common display area frame control unit that determines common display area based on display area information supplied from reception side terminal, and displays common display area on screen at transmission side terminal itself.