Abstract A FAB-SIMS/SNMS (fast atom bombardment secondary ion mass spectrometry and sputtered neutral mass spectrometry) apparatus has been studied. In the apparatus, an electron bombardment ionizer for ionization of sputtered neutrals and a quadrupole mass spectrometer for mass analysis are used. The primary beam is the fast oxygen atom beam with about 2.5 keV of the kinetic energy and 10 14 atoms/s of the intensity. Secondary ion spectra and sputtered neutral spectra are obtained in similar intensity for samples of a Cu-Be alloy and a polyethylene film. As the primary beam has no electric charge, even insulator samples are easily analyzed without any trouble caused by electrical charging on the sample surface.