An electronic circuit breaker of a power having dual output ports has an input port, two output ports, two field effect transistors, two current detection circuits and two control circuits. The control circuit has a silicon controlled rectifier (SCR) and an activation circuit detecting if a short circuit is present at one of the output ports through one of the current detection circuits, activating the SCR to turn off a corresponding FET after the occurrence of the short circuit, and disconnecting a corresponding output port from the input port. Due to the characteristics of the SCR, the SCR, once activated, stays in an on state between its anode and cathode. After the current of the output returns to its normal state, the FET is still turned off. Accordingly, high-frequency large current arising from alternately switching between the on and off states of the FET can be avoided.