A method for producing a probe of a thermal flowmeter for measuring mass flow of a medium in a measuring tube, wherein a probe core is provided arranged loosely in a probe sleeve having a longitudinal axis, wherein the probe sleeve is deformed relative to the longitudinal axis completely radially in the direction of the probe core by means of high energy rate forming, wherein a material-locking connection between probe sleeve and probe core results and a rod is formed, wherein the rod represents a base body that is used for probe production, wherein a deformation speed reaches values greater than 100 m/s, and wherein the high energy rate forming includes explosive forming or magnetic forming.