A spark plug comprising: a center electrode extending in a direction of an axial line defining an axis; an insulator having an axial hole which extends in the direction of the axial line and in which the center electrode is disposed; and a metallic shell disposed around the insulator, wherein the metallic shell has a first ground electrode which is electrically connected to the metallic shell and has a first surface facing a side surface of the center electrode in a radial direction so as to form a first gap, and a second ground electrode which is electrically connected to the metallic shell and has a second surface facing the side surface of the center electrode in the radial direction so as to form a second gap; a relation 60° ≤ θ ≤ 150° is satisfied, where θ is a smaller one of angles formed between a first line connecting the axis and a center of the first surface and a second line connecting the axial line and a center of the second surface when viewed from a forward end side (Df) toward a rear end side (Dr) of the spark plug in the direction of the axis; wherein the first ground electrode has a first ground electrode tip including the first surface, and a first ground electrode main body to which the first ground electrode tip is joined; and wherein the second ground electrode has a second ground electrode tip including the second surface, and a second ground electrode main body to which the second ground electrode tip is joined; characterized in that the metallic shell has a specific plane which bisects the metallic shell such that all the ground electrodes (30A, 30B) are located on one side of the plane; and wherein a projection length by which the first ground electrode tip projects from the first ground electrode main body inward in the radial direction of the metallic shell and a projection length by which the second ground electrode tip projects from the second ground electrode main body inward in the radial direction of the metallic shell are equal to or greater than 0.5 mm. a center electrode extending in a direction of an axial line defining an axis; an insulator having an axial hole which extends in the direction of the axial line and in which the center electrode is disposed; and a metallic shell disposed around the insulator, wherein the metallic shell has a first ground electrode which is electrically connected to the metallic shell and has a first surface facing a side surface of the center electrode in a radial direction so as to form a first gap, and a second ground electrode which is electrically connected to the metallic shell and has a second surface facing the side surface of the center electrode in the radial direction so as to form a second gap; a relation 60° ≤ θ ≤ 150° is satisfied, where θ is a smaller one of angles formed between a first line connecting the axis and a center of the first surface and a second line connecting the axial line and a center of the second surface when viewed from a forward end side (Df) toward a rear end side (Dr) of the spark plug in the direction of the axis; wherein the first ground electrode has a first ground electrode tip including the first surface, and a first ground electrode main body to which the first ground electrode tip is joined; and wherein the second ground electrode has a second ground electrode tip including the second surface, and a second ground electrode main body to which the second ground electrode tip is joined; characterized in that the metallic shell has a specific plane which bisects the metallic shell such that all the ground electrodes (30A, 30B) are located on one side of the plane; and wherein a projection length by which the first ground electrode tip projects from the first ground electrode main body inward in the radial direction of the metallic shell and a projection length by which the second ground electrode tip projects from the second ground electrode main body inward in the radial direction of the metallic shell are equal to or greater than 0.5 mm.