A snap cage for a ball bearing comprising: an annular main portion; and a plurality of bar portions protruding axially from the main portion at predetermined intervals in a circumferential direction, and each including a pair of claw portions disposed at a tip portion at intervals from each other, wherein a spherical pocket capable of holding a ball is formed between the adjacent bar portions, wherein the bar portion includes the pair of claw portions, and an outer circumferential surface thereof on a tip portion side is located on an inner diameter side with respect to an outer circumferential surface of the main portion, wherein on the inner diameter side of the cage, a plurality of lightened portions obtained by notching in the axial direction from an axial side surface of the main portion to the respective bar portions are formed separately at positions of the respective bar portions in a circumferential direction, and wherein each of the lightened portions is formed separately from a surface of the pocket and an axially outer surface of the bar portion formed between the pair of claw portions, wherein when an axial dimension of a wall portion (21, 22) formed between the axially outer surface of the bar portion and an inner wall surface of the lightened portion is T1 and an axial dimension of the main portion on a bottom portion of the pocket is T2, T2 > T1 is satisfied, characterized in that the outer circumferential surface of the bar portion on the tip portion side is located at a position between 1/2 and 3/4 of a radial thickness T of the main portion from an inner circumferential surface of the cage in a radial direction. an annular main portion; and a plurality of bar portions protruding axially from the main portion at predetermined intervals in a circumferential direction, and each including a pair of claw portions disposed at a tip portion at intervals from each other, wherein a spherical pocket capable of holding a ball is formed between the adjacent bar portions, wherein the bar portion includes the pair of claw portions, and an outer circumferential surface thereof on a tip portion side is located on an inner diameter side with respect to an outer circumferential surface of the main portion, wherein on the inner diameter side of the cage, a plurality of lightened portions obtained by notching in the axial direction from an axial side surface of the main portion to the respective bar portions are formed separately at positions of the respective bar portions in a circumferential direction, and wherein each of the lightened portions is formed separately from a surface of the pocket and an axially outer surface of the bar portion formed between the pair of claw portions, wherein when an axial dimension of a wall portion (21, 22) formed between the axially outer surface of the bar portion and an inner wall surface of the lightened portion is T1 and an axial dimension of the main portion on a bottom portion of the pocket is T2, T2 > T1 is satisfied, characterized in that the outer circumferential surface of the bar portion on the tip portion side is located at a position between 1/2 and 3/4 of a radial thickness T of the main portion from an inner circumferential surface of the cage in a radial direction.