Abstract: The present invention discloses a device for transmitting an audio and video (A/V) data in network, comprising a coder/transmission buffer coding and storing the A/V data, inputted from each of channels within a server providing the A/V data of one channel or multi channels for users connected to the network, to proper size fitting to the network states, and a user transmission controller transmitting a coded storing data on the coder/transmission buffer to the user, wherein the users are grouped with the user transmission controllers transmitting the coded data according to the network state of the group, while each of the user transmission controllers is allocated to each of the users connected to the server.