To develop measuring method for aerosolized carbon nanotubes (CNTs) in workplaces we evaluated the methods for quantifying CNTs by carbon analysis and the usefulness and responses of portable aerosol measuring instruments i.e., a light-scattering dust monitor and black carbon monitor for measuring CNT mass concentrations. CNTs aerosolized by the vortex shaker method were measured by these instruments and simultaneously collected on a quartz fiber filter. The responses of the portable instruments relative to the CNT concentration were evaluated, as well as the analytical conditions and procedure for quantifying CNTs by the thermal-optical carbon analysis of the CNTs collected on the filter.