To provide a manufacturing process of an alkaline earth metal carbonate particle and the alkali earth metal carbonate particle which has a form of a needle crystal or a columnar crystal with a controlled particle shape and an improved particle distribution.

The alkaline earth metal carbonate particle is obtained by reacting an alkaline earth metal ion with a carbonate ion. The manufacturing process involves a nucleus formation step and a crystal growth step. In the nucleus formation step, a solution of an alkaline earth metal salt and a carbonate solution are fed and reacted in a reaction vessel using a double jet method. When a1 and b1 respectively represent the average of the major axises and the minor axes of the alkaline earth metal carbonate particles after the nucleus formation step, a2 and b2 respectively represent the average of the major axises and the minor axes of the alkaline earth metal carbonate particles after the crystal growth step and Vr=(a2-a1)/(b2-b1) represents the ratio of the growth rate of the major axis to that of the minor axis after the crystal growth step, Vr is not less than 2.