Morphological control of hydroxyapatite (HAp) is very difficult because this compound has very low solubility. However, CaCO₃, a calcium salt with the same insolubility, dissolves easily in solutions containing CO₂. Therefore, HAp was easily dissolved by CO₂ blowing into the HAp suspension. The dissolution amount was 200 times that found without CO₂ blowing. Thus, a high-concentration HAp solution could be prepared through the simple process of CO₂ blowing. Moreover, flower-like HAp particles were deposited by outgassing the dissolved CO₂ in the HAp solution under heating.