Abstract: The measuring tube is for an electromagnetic flow meter and has a tube member made of a non-magnetic material that is provided with opposite through passages that have electrodes extended therethrough. An insulating lining of an enamel priming layer coats the inner surface of the tube member and fills the gaps between the electrodes and the tube member surfaces defining the through passages, the lining also including an covering enamel layer covering the priming layer surface that is within the tube member interior. The end faces of the electrodes that are in the tube member interior have the enamel material cleared therefrom. The priming layer may be formed by filling the tube member with a priming enamel slip, pouring out the slip material, cleaning the electrode end surfaces that are within the tube member interior and then heating to melt the slip material and then cooling. The covering layer may be formed by the same steps.