To make an electronic meeting seamless by sharing the same screen in real time.

A server terminal 10 includes an input part 11 capable of drawing input, an image data transmission part 12 for transmitting image data on a capture screen, a whiteboard 14 of transparent background for sharing a drawing screen from the input part 11, a display 16 for displaying the whiteboard 14 over a desktop work screen, and a control part 15 for controlling the server terminal 10. A client terminal 20 includes an input part 21 capable of drawing input, an image data reception part 22 for receiving the capture screen image data, a whiteboard 24 of transparent background for sharing a drawing screen from the input part 21, a display 26 for displaying the received image data as a shared screen and displaying the whiteboard 24 thereover, and a control part 25 for controlling the client terminal 20.