To provide a tool and method for simultaneously measuring the current and pressurizing force of a series welding machine.

When the current and the pressurizing force are simultaneously measured, a driving section 20 for pressurization makes an electrode supporting section 14 descend and applies both welding electrodes 16 and 18 to the conductive plate 50 of the tool 24 set on a work supporting section 22, thereby exerting the pressurizing force thereto. A pressurizing force detection signal SF is then outputted from the load cell 46 of the tool 24 and the signal SF is sent via a cable 25 to a resistance welding measuring instrument 32. Further, a welding source 26 supplies an AC voltage between both welding electrodes 16 and 18 via a welding transformer 28. A conducting path by the conducting plate 50 of the tool 24 is formed between the electrodes 16 and 18, and the current I flows in a secondary side circuit. A current detection signal S1 indicating the current I is outputted from a current sensor 44 and the signal S1 is sent via a cable 45 to the measuring instrument 32.