Quality control of the crystalline materials obtained from melts with the difficulty of nucleation is challenging. When nucleation is enhanced in such melts, the quality distribution is improved. Herein, the aeration method, which enhances nucleation in solution systems, was employed in a melt to investigate the aeration effect on nucleation in a melt and the effect of the crystallization conditions with aeration on the induction time τind. Experimental results show that aeration enabled nucleation in a melt under supercooling conditions, where nucleation could not occur without aeration. Furthermore, τind depended on the operating conditions with aeration (initial supercooling, aeration period, and atmospheric temperature). The crystal size in the obtained solid phase decreased as the atmospheric temperature decreased. These results suggest that the desired nucleation timing and crystal size can be obtained by manipulating the crystallizer and aeration conditions. Thus, aeration is promising for improving the quality distributions in crystalline materials.