A noble-metal chip (30, 90) joined to at least either a center electrode or a ground electrode, the center and ground electrodes forming a spark discharge gap, and having a circumferential edge of its facing end surface (31, 91) removed so as to form an edge-removed portion (32, 92). The edge-removal length is 0.01 mm or more and a ratio of the edge-removal length to a radius of the noble-metal chip is less than 0.3. The noble-metal chip is made of iridium or an alloy that contains iridium man amount of 70% by weight or more, and crystal grains constituting the noble-metal chip (30, 90) extends in the axial direction. Also disclosed is a method for manufacturing the spark plug.