Abstract: An output buffer is disclosed. In the prior art, when an output buffer swings to a supply voltage Vcc and a ground voltage Vss, the current drops rapidly at the supply voltage or the ground voltage, thereby generating bouncing of the supply voltage Vcc or bouncing of the ground voltage Vss. For eliminating this phenomenon, a capacitor is provided connected to an output node of the inventive output buffer to reduce the amount of the current flowing to the supply voltage terminal and the ground voltage terminal at the time point at which an output level is changed. Therefore, voltage drop and the bouncing of the supply voltage and the ground voltage is reduced by applying a precharge voltage which is precharged in the capacitor to the output node.