To provide a ground leakage breaker that sets a detection sensitivity from low sensitivity to high sensitivity by a mechanical setting with a simple configuration and is forcibly set to operate speedily.

When an extension slide switch 171b for switching sensitivity in a constraint setting section 170 is operated to move for setting a setting section 120 for switching the sensitivity to the high sensitivity (30 mA) in the ground leakage breaker, a protruding section 171a pushes out an extension slide switch 172b for time-delay interchange for movement, and a setting section 150 for time-delay interchange is forcibly set to high-speed operation (time delay: 0 ms).