The invention provides a burnt lime digester, belonging to the technical field of processing equipment of dry powdery calcium hydroxide, comprising a pre-digestion box body and one or more curing box bodies, wherein the pre-digestion box body is provided with a pre-digestion box cavity; the pre-digestion box cavity is internally pivoted with a pre-digestion stirring shaft; the pre-digestion stirring shaft is fixed with a group of pre-digestion stirring rods; a feeder nose is arranged at one end of the top part of the pre-digestion box body; a first flash cavity is separated by a first flash board at one end of the pre-digestion box cavity; the curing box body is provided with a curing box cavity which is communicated with the first flash cavity; the curing box cavity is internally pivoted with a curing stirring shaft which is fixedly provided with a group of curing stirring rods; a second flash cavity is separated by a second flash board at one end of the curing box cavity, which is characterized in that the second flash board is provided with a material level regulating gate in a sliding manner, and a material level regulating gate actuating mechanism is arranged on the curing box body. The technical scheme can save energy, improve yield and guarantee product quality.