The present invention relates to [1] alkali agent-containing particles which are free from deterioration of dissolvability in water and excellent in anti-caking property and which include (a) particles containing an alkali agent and having an average particle size of from 150 to 1000 μm, and a layer of (b) clay mineral particles exhibiting a water impregnation capacity of 200% by mass or more and having an average particle size of from 1 to 200 μm, the layer being formed on a surface of the respective particles (a); and [2] a method for suppressing caking of the alkali agent-containing particles including the step of forming a layer of the clay mineral particles (b) on a surface of the respective particles (a).