the device for pivoting an arbor of a rotating member , on a determined pivot axis , inside a timepiece movement includes at least one magnetic bearing including a magnet which exerts a force of attraction on a pivot made of magnetic material , of the arbor , and an endstone arranged between the magnet and the pivot , the endstone being formed of a material having a hardness greater than 500 hv and a friction coefficient less than or substantially equal to 0 . 1 with the material of which the pivot is made . the material forming the endstone has a high magnetic permeability and the endstone has , in cross - section to the pivot axis , smaller dimensions than those of the magnet , said endstone being arranged in the timepiece movement to be centred on the determined pivot axis .