At the last stage of a level converter that provides an internal signal to an internal signal output node, MOS transistors that are rendered conductive alternatively are provided as current source transistors. These additional MOS transistors are selectively rendered conductive according to the voltage level of, for example, a bonding pad. The charging/discharging current towards the internal node can be adjusted. Accordingly, the rising time and falling time of the internal signal can be constantly made equal. Thus an input/output circuit that can provide a signal at a proper timing even when the operating environment such as the system power supply voltage changes can be implemented.