The present invention relates to a semi-automatic scanner for ultrasonic inspection of a branch pipe weld that has a small size and is able to perform an inspection while moving in a state of being attached to a test object by a magnetic force, thereby being applied to fittings having various shapes, such as a branch pipe and an elbow. The semi-automatic scanner for ultrasonic inspection according to the present invention includes a probe configured to inspect a weld by irradiating ultrasonic waves onto a surface of a test object, a probe holder configured to couple the probe by applying an elastic force so as to be pressed against the surface of the test object, an installation bracket having a rod shape, to which the probe holder is coupled so as to be laterally movable, four wheel units installed on both front and rear side surfaces of the installation bracket so as to be vertically slidable, and four magnet parts, each of which is installed on one of the four wheel units and presses the one of the wheel units against the test object with a magnetic force.