An apparatus for detecting a phase transition of a food sample includes: a support base for supporting a food sample which contains moisture and which is able to undergo phase transition between a solid and a liquid; a light penetration unit for permitting near-infrared light containing a light having a wavelength of absorption peak of water and a light having a wavelength of absorption peak of ice to penetrate into the food sample supported by the support base; a spectroscopic unit for dispersing the near-infrared light which is from the light penetration unit and which has transmitted and reflected in the food sample, and measuring a light intensity over a time; an absorbance-and-ice-weight-ratio calculation unit for calculating, on the basis of a spectroscopic data of the near-infrared light obtained by the spectroscopic unit, an absorbance of water and an absorbance of ice in the food sample and calculating an ice weight ratio with respect to a frozen moisture; an absorbance differential calculation unit
