Free convection generated in the fluid temperature difference by local heating, influences that can`t be ignored in heat transfer characteristics. Therefore, it is required to measure the amount of heat generated up to the free convection occurs. In previous studies, we've been estimated for the temperature distribution and the free convection around the micro heating magnetic sphere of mm size in the water. In this study, the micro particles under the alternating magnetic field over time imaging the absorbance at a wavelength of 1150 nm or 1412 nm, to estimate the temperature distribution by obtaining the absorbance of images. This time, we set up micro particles in the syrup, to estimate the temperature distribution from the absorbance image.