A roller bearing cage formed by bending a steel strip having a plurality of pockets for accommodating rollers into a ring shape and joining the ring-shaped steel strip, characterized by comprising: a first ring portion and a second ring portion which form a pair and a plurality of cage bars connecting the first ring portion and the second ring portion and extending in an axial direction O of the cage, wherein the first ring portion has a first radially outer guide surface so that the cage is guided along its outer periphery, the second ring portion has a second radially outer guide surface so that the cage is guided along its outer periphery, the cage bar has a third radially outer guide surface formed in its middle part so that the cage is guided along its outer periphery, the cage bar has a first recess and a first roller guide surface at a position located closer to the first ring portion than the middle part is, the first recess being recessed toward a radially inner side of the cage with respect to the first radially outer guide surface and the third radially outer guide surface, and the first roller guide surface protruding toward the radially inner side with respect to a radially inner surface of the first ring portion, and the cage bar further has a second recess and a second roller guide surface at a position located closer to the second ring portion than the middle part is, the second recess being recessed toward the radially inner side of the cage with respect to the second radially outer guide surface and the third radially outer guide surface, and the second roller guide surface protruding toward the radially inner side with respect to a radially inner surface of the second ring portion, characterized by a radial thickness of the cage bar in the radial direction of the cage being equal to or larger than that of the first ring portion and being equal to or larger than that of the second ring portion, and the pitch circle of the rollers being located within the radial thickness range of the cage bar with regards to the whole length of the cage bar from its one end to the other end in the axial direction. a first ring portion and a second ring portion which form a pair and a plurality of cage bars connecting the first ring portion and the second ring portion and extending in an axial direction O of the cage, wherein the first ring portion has a first radially outer guide surface so that the cage is guided along its outer periphery, the second ring portion has a second radially outer guide surface so that the cage is guided along its outer periphery, the cage bar has a third radially outer guide surface formed in its middle part so that the cage is guided along its outer periphery, the cage bar has a first recess and a first roller guide surface at a position located closer to the first ring portion than the middle part is, the first recess being recessed toward a radially inner side of the cage with respect to the first radially outer guide surface and the third radially outer guide surface, and the first roller guide surface protruding toward the radially inner side with respect to a radially inner surface of the first ring portion, and the cage bar further has a second recess and a second roller guide surface at a position located closer to the second ring portion than the middle part is, the second recess being recessed toward the radially inner side of the cage with respect to the second radially outer guide surface and the third radially outer guide surface, and the second roller guide surface protruding toward the radially inner side with respect to a radially inner surface of the second ring portion, characterized by a radial thickness of the cage bar in the radial direction of the cage being equal to or larger than that of the first ring portion and being equal to or larger than that of the second ring portion, and the pitch circle of the rollers being located within the radial thickness range of the cage bar with regards to the whole length of the cage bar from its one end to the other end in the axial direction.