Implementing strategies for single-molecule fluorescence detection in a sheathed flow, NanoFCM provides a versatile and powerful platform —— Flow NanoAnalyzer for the multiparameter analysis of functional nanoparticles (7-500 nm) at the single-particle level. By precise quantification of the ultraweak elastically scattered light from single nanoparticles, high-resolution size distribution comparable to that of electron microscopy can be acquired in 1-2 minutes. Biochemical properties of single nanoparticles can be analyzed via concurrent multi-color fluorescence detection. Flow NanoAnalyzer has the capacity to measure the size, concentration, and biological properties of nanoparticles. To our knowledge, Flow NanoAnalyzer is the only flow cytometry instrument that covers the size range of exosomes (30-120 nm). Flow NanoAnalyzer is therefore expected to become a powerful tool for life science, nanoscience and nanotechnology studies.