A rotary changer for welding torches, the changer being configured to replace a cylindrical or bar-shaped torch component screwed on, and coupled to, a tip portion of a body of a welding torch, the changer comprising: a rotator arranged rotatably on a rotational axis and having i) an opening located at one end of the rotator, and ii) a hollow into which the torch component is insertable through the opening such that a center axis of the torch component is aligned with the rotational axis of the rotator; and an interlocking member configured to rotate integrally with the rotator and to be movable in a direction intersecting with the rotational axis, the interlocking member including an interlocking portion (60a, 60b) on one side of the interlocking member facing the rotational axis, the interlocking portion (60a, 60b) being interlockable with the torch component, wherein the rotator rotates with the interlocking portion (60a, 60b) interlocked with the torch component, thereby turning the torch component on its center axis to either remove or attach the torch component from/onto the tip portion of the torch component's body, characterized in that the rotator comprises a cam means including a sliding portion and a cam portion, the sliding portion being slidable along its rotational axis and configured to slide toward the other end of the rotator when pressed by the torch component being inserted into the hollow, the cam portion being configured to move the interlocking member toward the rotational axis while the sliding portion is sliding toward the other end of the rotator. a rotator arranged rotatably on a rotational axis and having i) an opening located at one end of the rotator, and ii) a hollow into which the torch component is insertable through the opening such that a center axis of the torch component is aligned with the rotational axis of the rotator; and i) an opening located at one end of the rotator, and ii) a hollow into which the torch component is insertable through the opening such that a center axis of the torch component is aligned with the rotational axis of the rotator; and an interlocking member configured to rotate integrally with the rotator and to be movable in a direction intersecting with the rotational axis, the interlocking member including an interlocking portion (60a, 60b) on one side of the interlocking member facing the rotational axis, the interlocking portion (60a, 60b) being interlockable with the torch component, wherein the rotator rotates with the interlocking portion (60a, 60b) interlocked with the torch component, thereby turning the torch component on its center axis to either remove or attach the torch component from/onto the tip portion of the torch component's body, characterized in that the rotator comprises a cam means including a sliding portion and a cam portion, the sliding portion being slidable along its rotational axis and configured to slide toward the other end of the rotator when pressed by the torch component being inserted into the hollow, the cam portion being configured to move the interlocking member toward the rotational axis while the sliding portion is sliding toward the other end of the rotator.