A microbial pesticide composition obtained by a method, said method comprising: a step for adjusting a liquid culture medium of a bacterium belonging to the genus Bacillus to pH 3.0-5.0 (pH adjustment step); a step for mixing the liquid culture medium with calcium chloride and/or magnesium sulfate (mixing step); and a step for freeze drying or spray drying the mixture (drying step). Even when the microbial pesticide composition according to the present invention is stored for a long time at room temperature, the active ingredient thereof remains stable and a sufficient plant disease control effect is maintained.