The invention discloses an orthogonal ion source device. The orthogonal ion source device comprises a three-dimensional ionization chamber and an ion lens set, wherein the three-dimensional ionization chamber comprises an ion exclusion electrode, a thermionic emission filament, an electronic reception well, a direct sample feeding tube and a sample heating tungsten filament, and the ion lens set comprises ion extraction electrodes, ion focusing electrodes, ion accelerating electrodes and ion outlets. In an X-axis direction of the ionization chamber, the ion exclusion electrode, the sample heating tungsten filament and the ion lens set are positioned on a same straight line; in a Y-axis direction of the ionization chamber, the thermionic emission filament faces the electronic reception well directly; in a Z-axis direction of the ionization chamber, the sample feeding tube faces the heating tungsten filament directly. The orthogonal ion source device has the advantages that direct liquid sample feeding is achieved; the heating tungsten filament is capable of heating a sucked sample and performing electron bombardment on the same at the same time; by means of controlling current of the heating tungsten filament, background interferences are reduced; the orthogonal ion source device mainly generates single-charge ions in an ionization mode, is little in energy dissipation, simple in spectral lines and applicable to quick ionization of metal elements in a water body which is difficult to volatilize.