An apparatus for a manufacturing semiconductor device including a plate member and a joint member. The apparatus includes a plate-type tool having the plate member mounted thereon, a first fixing tool and a second fixing tool having an inclined surface for abutting an upper edge of an end part in a width direction of plate member. The second fixing tool is fixed onto the plate-type tool adjacent to the end part. An ultrasonic horn applies ultrasonic vibration in the width direction of plate member while pressing the joint member toward the plate member.