The present disclosure sets out a contact welding tool having at least one heating element for contacting a workpiece and at least one heat source for heating the heating element, at least one heat source being an infrared radiation source emitting infrared radiation in the short-wave infrared range. The present disclosure also sets out a method for operating a contact welding tool wherein a heating element of the contact welding tool is heated by means of short-wave infrared radiation and then the heating element is brought into contact with a workpiece to be reshaped. The present contact welding tool and method can be used particularly advantageously for heat staking, for example of plastic rivets.