Roundness measurement disc

The utility model relates to a roundness measuring tool for a tyre die, in particular to a roundness measurement disc. The technical scheme is that the roundness measurement disc mainly consists of a disc table, a bearing seat, a tapered roller bearing, a lifting sleeve, a shaft, a connecting rod, a dial indicator and a standard die sleeve, wherein the center of the disc table is movably connected with the shaft vertical to the disc table, the other end of the disc table is fixed with the standard die sleeve, the shaft is provided with the lifting sleeve capable of moving up and down, and one side of the lifting sleeve is connected with the dial indicator through the connecting rod. The utility model has the advantages that the operation is simple, and the manufacturing cost is low; the measuring instrument is manually operated and can be operated by a fitter without being operated by a specially-assigned person or compiling programs, thereby effectively improving the product quality and the working efficiency.