An inertial mass with adjustment of inertia and/or unbalance for a horological resonator, including a plurality of mobiles for adjusting inertia and/or unbalance, toothed or fluted, each mounted pivotably about a mobile axis with respect to a flange that the inertial mass includes, and with a centre of mass off-centre with respect to this mobile axis, each mobile cooperating by meshing with an inertia and/or unbalance adjustment crown, toothed or fluted, under a permanent constraint exerted by an elastic return force exerted by the crown and/or the mobile.