A flat panel lighting apparatus, which makes it easy to replace a circuit board with LEDs thereon, is provided. The flat panel lighting apparatus includes a backplate, a driving unit, a light guide plate, a frame, a bracket, a circuit board, a connector and a cable connecting the driving unit and the circuit board. The frame with an opening portion is disposed at an outer periphery of the backplate and the light guide plate. The bracket is detachably coupled to the opening portion of the frame. The circuit board with light sources, is disposed in a space between the frame and the light guide plate, and is replaceable in a sliding type through the opening portion of the frame when the bracket is decoupled from the frame. The connector has a female terminal attached to the circuit board and a male terminal detachably coupled to the female terminal.