We have been studying a new method of pulsed-laser melting in liquid, which is a unique and promising technique for the fabrication of submicrometer-sized spherical particles of various materials. However, spherical particles sometimes did not form depending on the raw particles, even when we used the same material. In this study, we clarified experimentally that particle aggregation in a suspension is important for spherical particle formation, and we found that the addition of an electrolyte to induce particle aggregation effectively promotes spherical particle formation.