PRESSURE WELDING DEVICE

PROBLEM TO BE SOLVED: To provide a multi-harness pressure welding device that can pressure-weld and cut a short electric wire group and does not increase in cycle time, and its pressure welding method.SOLUTION: A pressure welding method for a multi-harness body that has a parent connector pressure-welded to one end of a plurality of electric wires and a plurality of child connectors pressure-welded to the other end for each of electric wire groups differing in electric wire length, includes: a child-side pressure welding step of collectively pressure-welding the electric wires while holding the child connectors by a child-side connector guide part 30; an opening step of opening the child connectors from the child-side connector guide part; an electric wire length measuring step of measuring a length of each electric wire from an electric wire group on one width-directional side of electric wires to an electric wire group on the other side while the electric wire groups pressure-welded to the child connectors are parallel; and a parent-side pressure welding step of holding the parent connector by a parent-side connector guide part 70 and pressure-welding from the electric wire group parallel in a width direction to the electric wire group on the other side, and cutting them.