To provide an inexpensively-installable and automatically-openable scouring gate.

This scouring gate 10 is installed in a notched section 2 of a weir 1 of a dam so as to discharge sand in the dam to the downstream side of the weir 1. The scouring gate 10 is equipped with a closing member 20 which is supported in such a swingable manner as to be switchable between the state of abutting on the downstream-side surface of the weir 1 so as to cover the notched section 2 and the state of being isolated from the downstream-side surface of the weir 1. Constitutionally, the closing member 20 abuts on the downstream-side surface of the weir 1 in normal conditions, and is isolated from the downstream-side surface of the weir 1 by being swung by water pressure when the water pressure acting on the closing member 20 from the upstream-side of the weir 1 exceeds predetermined one.