To provide a backlight driving circuit making the backlight driving circuit and backlight not to break down.

A pulse judging circuit 400 consists of a NOT circuit 41, an integrating circuit 42, and an AND circuit 45. A driving pulse input terminal 40 is connected with one of the terminals of the AND circuit 45, and also connected with the NOT circuit 41. Further, a resister 43 of the integrating circuit 42 is connected with the NOT circuit 41 in series, and the other end of the resister 43 is connected with the other terminal of the AND circuit 45. Moreover, one end of a capacitor 44 is connected with the other end of the resistor 43, and the other end is grounded. Thus, it is possible to prevent the backlight driving circuit and the backlight from being made faulty as the result that an abnormal driving pulse with a wide pulse width is inputted and causes a longer ON-time of a MOSFET in the backlight driving circuit and an over current.