A mass flowmeter of the Coriolis type with a tube through which a medium flows during operation and with excitation means for causing the entire tube or part thereof to perform a rotational vibration about a primary axis of rotation during operation. The excitation means are electromagnetic and designed such that they do not make contact with the tube during operation and have no components that are fastened to the tube. More in particular, the tube is made of an electrically well conducting material, and the excitation means comprise first means for causing an electric current to flow through the tube during operation and second means for generating a magnetic field at the area of a portion of the tube, which magnetic field is perpendicular to the direction of the current and in operation either the current or the magnetic field changes its sign periodically, with the result that the (Lorentz) force generated by the product of current and magnetic field causes a rotational oscillation of the entire tube or a portion thereof about the primary axis of rotation
