To obtain a spindle motor which can be disassembled easily by a simple structure.

The bearing holder 3 of a stator 1a is composed of a cylindrical holder body 3a fitted with a bearing 4, and a bottom lid 3b wherein a single split stopper ring 9 is arranged on the bottom lid 3b, an annular groove 5a formed at the end of the shaft 5 of a rotor 1b is fitted over the stopper ring 9 by pushing the shaft 5 into the central hole of the stopper ring 9 through the bearing 4 and the rotor 1b is rotated at high speed by exciting a driving coil 2. In such a spindle motor 1, the bearing holder 3 is divided into the holder body 3a and the bottom lid 3b and a means R for coupling the bottom lid 3b with the holder body 3a is composed of an externally threaded portion 15 formed on the outer circumferential surface at the end of the holder body 3a, and an internally threaded portion 17 formed on the inner circumferential surface at the circumferential wall portion 16 of the bottom lid 3b and being screwed to the externally threaded portion 15.