In the study of the working mechanisms of multicellular systems, the measurement of chemical quantities (gene expression and metabolism) has been the main approach. However, in tissue formation and force generation, mechanical quantities (force, elasticity) inside and outside the cells are involved. To understand the complex network intervening between chemical and mechanical quantities, it is necessary to measure both chemical and mechanical quantities in living cell systems. In recent years, bioimaging methods using Brillouin scattering have been attracting attention as a method to measure the mechanical quantities in living cells. Brillouin scattering is a type of inelastic scattering, and the frequency shift due to Brillouin scattering is proportional to the propagation velocity of acoustic phonons in the medium. Since the speed of acoustic phonon depends on the elastic constants, the elastic properties can be estimated from the frequency shift. We have been developing Brillouin scattering microscopy for applications in developmental biology and mechanobiology. The imaging system was designed and constructed with the target of observing the inside of living cells. We have achieved not only imaging of single cells, but also of ES cell colonies, tissues and organs in model organisms. We are also working on simultaneous measurements with other optical modalities (fluorescent protein, Raman scattering, etc.) to advance biological interpretation. Correlation between multiple features related to cellular state will be discussed.