The effects of phenol-binding (Ph-binding) and temperature on the Young's moduli, the volumes, and the nanostructures of N-isopropylacrylamide (NIPA) and N, N-diethylacrylamide (DEA) hydrogels were investigated. The modulus and volume of the NIPA gel varied discontinuously with respect to the Ph concentration of solution outside the gel and temperature, while those of the DEA gel varied discontinuously with respect to the Ph concentration, but continuously with respect to temperature. The large relaxation of the modulus observed only in the case of the shrunken gels could be described by a power function of time elapsed after stretching the gel. The small-angle X-ray scattering spectra obtained for the Ph-binding NIPA and DEA gels exhibited the broad peaks indicating the regular distribution of the electron-rich entity with the periodic length about 1.2 nm. The shrunken NIPA and DEA gels were found to reswell and decrease their moduli at Ph concentrations much higher than the critical transition concentration. These results demonstrate the attractive interaction between the phenol molecules and the amide group of NIPA or DEA gel that induces the volume phase transition and condenses the phenol in the chain networks.