An object is to effectively reduce the difference in stress occurring between a tip and an annular portion, to thereby prevent separation and cracking of the tip more reliably. A spark plug (1) includes an insulator (2) having an axial hole (4), a center electrode (5) inserted into the axial hole (4), a metallic shell (3) provided around the insulator (2), aground electrode (27) whose base end portion is fixed to the metallic shell (3) and which has an annular portion (27A) formed at a forward end portion thereof, the center electrode (5) being disposed radially inward of the annular portion (27A), and an annular tip (32) which is joined to the inner circumference of the annular portion (27A) and which forms a spark discharge gap (28) between the center electrode (5) and the inner circumferential surface of the annular tip (32). Recesses (35) are provided on at least one of the inner and outer circumferences of the annular portion (27A).