TDNMR is a nuclear magnetic resonance spectrometer that observes the relaxation time of protons. TDNMR does not require deuterium solvents as in high-resolution NMR, and can be used to measure samples without sample preparation. This paper introduces an example of using TDNMR to evaluate cross-linking of rubber and polymers. While it is possible to evaluate cross-linking by physical properties based on relaxation time, it is also possible to evaluate cross-linking from a structural viewpoint by using the MQ method, which can detect the effect of residual dipole interactions caused by cross-linking. In addition, examples of the application of the MQ method to polymers will be presented.