The invention relates to a light source device 100. The light source device 100 comprises a roughly inverted T shaped light source base 10, wherein a storing chamber A is inwards concavely formed in one end of the light source base 10, and an electric connecting part 101 which is electrically connected to the light source device 100 is arranged in the storing chamber; a first circuit board 20 which is electrically connected to the electric connecting part 101 is arranged at the upper side of the electric connecting part 101; the first circuit board 20 and a lens module 30 form a light source chamber B; a heat dissipating part 40 and a second circuit board 50 which clings to the outer side of the heat dissipating part 40 are stored in the light source chamber B, and the second circuit board50 is provided with a plurality of side surfaces and a top surface; a plurality of LED light sources 60 are distributed on the second circuit board 50. According to the light source device, an innerhexagonal prism type lens is arranged in the lens module 30 and enables uniform lighting of a cob light source; the light source device is soft in rays and nice in appearance.