<p>A welding apparatus capable of rapidly following up the abrupt change of the surface of a work in the vertical and horizontal directions by increasing the responsiveness thereof to the change of the attitude of a welding torch and a welding method. The welding apparatus comprise a first movable member (20) supported on a base member (10) movable in the X-axis direction movably in the Y-axis direction orthogonal to the X-axis direction, a second movable member (30) supported on the first movable member rotatably around a Z-axis orthogonal to a plane formed by the X-axis and the Y-axis, and the welding torch (40) supported on the second movable member.</p>
