An apparatus for setting a gap between a first electrode and a second electrode of a spark plug, encompassing at least a counter-brace, a gap plate, and a plunger, which are disposed along a longitudinal axis; the counter-brace being configured to brace the spark plug; the gap plate being disposed between the counter-brace and the plunger in the direction of the longitudinal axis; the gap plate being configured to be disposed between the first electrode and the second electrode; and the plunger being configured to apply a deformation force in the direction of the longitudinal axis onto the second electrode.