There are provided a split outer ring which can suppress the reduction in durability and which can suppress largely the generation of noise or vibration which is caused in association with the passage of rolling elements over a mating surface and a split rolling bearing which employs the same outer ring.A split outer ring 2 according to the invention has first and second split outer ring members 5, 6 which are formed into a cylindrical shape by being butted against each other at circumferential end portions. First flat plane portions 7 and a V-shaped recess portion 8 which is recessed in a circumferential direction are formed at one end portion 5a of the circumferential end portions which are butted against each other. Secondary flat plane portions 9 which are to be brought into abutment with the first flat plane portions 7 and a projecting portion 10 which projects in the circumferential direction from the second flat plane portion 9 so as to be introduced into the recess portion 8 are formed at an end portion 6a which is to be butted against the end portion 5a. A space S is formed between the recess portion 8 and the projecting portion 10 so as to avoid a contact between a bottom portion 8b of the recess portion 8 and a vertex portion 10b of the projecting portion 10.