The invention concerns a microsystem, in particular for producing microswitches or microvalves, constituted on a substrate (50) and used for producing a shift between a first operating state and a second operating state by means of a heat actuated device with bi-metal switch effect. The heat-actuated device comprises a deformable element (51) connected, by opposite ends, to the substrate (50) so as to present naturally a deflection without stress relative to the substrate surface which faces it, said natural deflection determining the first operating state, the second operating state being produced by the heat-actuated device which induces, by the effect of temperature variation, a deformation of the deformable element (51) tending to reduce its deflection and submitting it to a compressive stress by buckling effect in a direction opposite to its natural deflection.