To provide a light diffusion member which can be manufactured inexpensively, has sufficient rigidity and shows different light diffusion characteristics according to a direction, a light transmission type screen, an interactive board, and an interactive board system.

A mesh layer 15 has a light diffusion effect for diffusing light made incident from one surface and emitting the light from the other surface, is like a sheet, and includes a net-like member 151 including at least a first thread-like member group 151a comprising a plurality of thread-like members made of resin, arranged at a predetermined interval in a first direction parallel with a sheet surface and a second thread-like member group 151b comprising a plurality of thread-like members made of resin, arranged at a predetermined interval in a second direction which is parallel with the sheet surface and different from the first direction. The second thread-like member group 151b is more densely arranged than the first thread-like member group 151a. The transmission type screen 10 having such a mesh layer 15, the interactive board 50 and the interactive board system are provided.