A fine A-type zeolite particle having an average primary particle size of 0.1 &mgr;m or less and a variation coefficient of 90% or less, wherein a ratio of a peak area above a background level to all peak are in the range of 2&thgr;=20° to 40° in a powder X-ray diffraction spectrum of said fine A-type zeolite particle is 30% or more; a process for preparing the fine A-type zeolite particle, comprising reacting a silica source with an aluminum source in the presence of an organic compound having an oxygen-containing functional group and a molecular weight of 100 or more; and a detergent composition comprising a surfactant and the fine A-type zeolite particle. The fine zeolite particle is suitably used for detergent builders, water treatment agents, fillers for paper, resin fillers, oxygen-nitrogen separating agents, adsorbents, catalyst carriers, soil improvers for gardening, polishing agents, and the like.