To improve the dispersion stability of alkaline builder particles in a pasty detergent composition.

This pasty detergent composition comprises a surfactant and the alkaline builder particles which satisfy both of the following conditions (A) and (B) in the pasty detergent composition: (A)≥1.5 slope (n) of the least squares approximation straight-line of a graph obtained by plotting values of logD (D denotes the particle diameter of the alkaline builder particles) as the abscissa axis versus values of log.log(100/R) (R denotes the mass ratio of respective particles having the particle diameter D) as the ordinate axis; and (B) ≤50 μm mass 50% diameter.