A double-split cage includes a strip-shaped metallic sheet curved into a semi-cylindrical shape and having several pockets for accommodating a single row of rollers arranged in the circumferential direction. The strip-shaped metallic sheet has two arch portions separately arranged in the axial direction and includes pillar portions arranged at several positions of both arch portions in the circumferential direction. Both arch portions have protrusions protruding from the pillar portions at both end portions in the circumferential direction, and a forward end portion of each protrusion is chamfered at a corner outside in the axial direction. Length of the chamfered portion in the circumferential direction is larger than the protruding length of each protrusion.