A cylindrical battery is provided, which includes a case, a positive pole and an insulation sealing member. The case is a cylindrical groove structure. The positive pole is riveted to the case, and the insulation sealing member is arranged between the positive pole and the case. The insulation sealing member comprises an upper insulation sealing member and a lower insulation sealing member, the upper insulation sealing member is arranged outside the case and is engaged with and connected to the case, and the lower insulation sealing member is arranged inside the case. At least one of the upper insulation sealing member and the lower insulation sealing member is provided with an annular protrusion block, the annular protrusion block fits closely against an outer sidewall of a portion, passing through the case, of the positive pole, and the outer sidewall of the portion, passing through the case, of the positive pole presses the annular protrusion block towards an inner sidewall of a portion, being passed through, of the case.