RESISTANCE-WELDING DEVICE

To provide a resistance-welding device that can reduce variation in inner pressure during expansion and contraction of a cover member without deteriorating a cover function.SOLUTION: An electrode movement mechanism 18 of a welding gun 10 comprises: a first mechanism part 41 having a shaft 26; a second mechanism part 43 that has a housing 24 which can store at least part of the shaft 26 and supports the shaft 26 relatively movably in a shaft direction; and a cover member 32 that covers at least part of the shaft 26 and can expand and contract accompanying relative displacement of the first mechanism part 41 and the second mechanism part 43, in which is formed a communication path CP through which an inner space ISc between the shaft 26 and the cover member 32 is communicated with an inner space ISh of the housing 24.SELECTED DRAWING: Figure 2 【課題】カバー機能を低下させることなく、カバー部材の伸縮時における内圧変化を小さくできる抵抗溶接装置を提供する。【解決手段】溶接ガン１０の電極移動機構１８は、シャフト２６を有する第１機構部４１と、シャフト２６の少なくとも一部を収納可能なハウジング２４を有するとともに、シャフト２６を軸方向に相対移動可能に支持する第２機構部４３と、シャフト２６の少なくとも一部を覆い、第１機構部４１と第２機構部４３との相対変位に伴って伸縮可能なカバー部材３２と、を備え、シャフト２６とカバー部材３２との間の内部空間ＩＳｃと、ハウジング２４の内部空間ＩＳｈとを連通させる連通路ＣＰが形成されている。【選択図】図２