Ostwald ripening of KNO3 grains in acrylamide gel was investigated for the grain’s volume fractions of 0.05 and 0.10. The grains observed were rodlike at the initial stage but became spherical with ripening. The sizes and the number densities of the spherical grains were measured, and power relations for them against the ripening time t were obtained. At the low volume fraction (0.05) the exponents of the power relation with respect to the average size and the number density, respectively, were 0.365 and -0.66 for t = 20-800 h, while at the high volume fraction (0.10) they were 1.39 and -1.93 at the early stage t = 70-167.7 h but 0.34 and -0.88 at the late stage t = 167.7-900 h. The size distribution functions were unimodal for the low volume fraction and multimodal for the high volume fraction. The function at the low volume fraction for t = 20-50 h was found to be described by the reaction-controlled parabolic growth. The functions normalized by the average sizes became close to the Lifshitz-Slyozov-Wagner function as t increased. The present experimental results suggest that the concentration fluctuation at the initial period influences the growing behaviors of the grains for a long period.