A process for preparing detergent particles containing step (I): mixing a base particle for supporting a surfactant ((a) component), and a surfactant composition ((b) component), under mixing conditions wherein the (a) component does not substantially undergo breakdown, to give a mixture; wherein the base particle is obtained by spray-drying an aqueous slurry, wherein the mixing operation is carried out by using a mixer containing agitation impellers, and where the mixer further contains disintegration impellers, the mixing operation step (I) is carried out without substantially rotating the disintegration impellers; and step (II): mixing the mixture obtained in step (I) with 5 to 100 parts by weight of fine powder, while substantially maintaining the shape of the (a) component containing (b) component, to give detergent particles, having a degree of particle growth of 1.3 or less, and a bulk density of 500 g/L or more.