An electrode of the spark plug includes a first melt portion formed between a body portion of an intermediate member and a noble metal tip; and a second melt portion that is formed, between a flange portion of the intermediate member and an electrode base material, at least at a position of intersection with an axial line of the noble metal tip. In a cross section including the axial line of the noble metal tip, when: a diameter of the noble metal tip is denoted by Tw; the shortest distance between the second melt portion and a boundary between the first melt portion and the intermediate member is denoted by S1; and the longest distance between the second melt portion and the boundary between the first melt portion and the intermediate member is denoted by S2, 1.0 mm≤Tw≤1.2 mm and (S2−S1)≤0.3 mm are met.