An illuminated keyboard includes a main circuit board, a membrane switch circuit module and an illumination circuit board. The membrane switch circuit module includes a first connecting zone and a bus bar. Through the bus bar, the membrane switch circuit module is connected with the main circuit board. The illumination circuit board includes a second connecting zone. The second connecting zone and the first connecting zone are connected with each other. Consequently, the illumination circuit board is electrically connected with the main circuit board through the second connecting zone, the first connecting zone and the bus bar.