The invention provides a method for producing a spark plug, which can improve the accuracy of judging whether a welding position of the tip is good or not. The method for producing a spark plug includes: a welded metal detection step of detecting an edge of a welded metal formed around the tip; a center calculation step for calculating the center C of the contour of the welded metal on the basis of the edge of the welded metal detected by the welded metal detection step; and a tip detection step for detecting the edge of the tip within a first range defined by a first annular imaginary line that is closer to the center C side than the contour of the welded metal and that is centered on the center C, and determining whether or not the tip is good on the basis of the position of the edge ofthe base material and the position of the edge of the tip detected by the tip detection step.