A method for making a flexure bearing for an oscillator with an inertial element oscillating in a plane supported by flexible strips fixed to a stationary support returning it to a rest position includes: forming the bearing with basic strips in superposed levels, each having an aspect ratio of less than 10; breaking down the number of basic levels into a plurality of sub-units, each including one or two strips joining a basic support and a basic inertial element, which are made by etching substrates; assembling the sub-units by joining their basic inertial elements; and fixing the basic supports to the support, directly or via translational tables along one or two in-plane translational degrees of freedom, of lower translational stiffness than that of the sub-unit.