Abstract: A foldable lighter that prevents inadvertent ignition by erroneously pressing the operating button when folding the swing-arm to make the lighter compact. A foldable lighter 1 that comprises a lighter body 2 that contains a fuel tank, a piezoelectric unit 102, an operating button 8, and a swing-arm 4 connected with free swinging to one end of lighter body 2 and that incorporates a locking mechanism to prevent accidental depression of operating button 8. The locking mechanism consists of a projecting portion 74 formed in a predetermined range of cylindrical walls 26a and 26c made integrally with swing-arm 4 and a hook 8b that extends from the operating button along a portion of the cylindrical walls.