Small angle neutron scattering (SANS) is an important technique in order to study both the structural and dynamical properties of a wide range of substances in soft condensed matter [1 A. Arbe, et al., Soft Condensed Matter, http://www.sfn.asso.fr/PromoNeutron/SoftMat.pdf  [Google Scholar]]. Soft condensed matter includes a large class of molecular masterials, i.e., polymers, liquid crystals, micellar solutions, microemulsions, and colloidal suspensions, as well as biological materials, e.g., membranes, vesicles, proteins, enzymes, etc. These substances are interesting both for basic research and commercially as functional materials. Since the complexity of the structures of soft condensed matter systems for some applications will increase in the future, it is posing challenging problems to basic science. Herewith, the SANS technique, which is one of the advanced tools to investigate the static and dynamic structures of soft condensed matter systems, will be described intensively for a wide variety of experiments, including in-situ measurements.