A circuit board includes a substrate and a supporting frame fixed to, and supporting, the substrate. The supporting frame includes a main body, a pressing supporting portion, two pulling supporting portions and two fixing portions. The main body includes a first arm and a second arm connected to the first arm. The pressing supporting portion extends downwards from a junction of the first arm and the second arm for counterbalancing a downward force applied upon the substrate. The pulling supporting portions respectively extend downwards from distal ends of the first arm and second arm for counterbalancing an upward force applied upon the substrate. The two fixing portions are respectively formed on the first arm and second arm. Each of the fixing portions is located between the pressing supporting portion and one corresponding pulling supporting portion and is closer to the corresponding pulling supporting portion.