A device for estimating survival cell count which estimates a survival cell count of a bifidobacteria strain or a lactic acid bacteria strain contained in a composition after storage, wherein said composition is a probiotic product, and wherein the device comprises: an input receiver which receives an input of information on conditions for calculating the survival cell count, which presents a storage period of the composition containing said strain, a viable cell count of said strain contained in said composition at the initiation of storage, a storage temperature of said composition, and a water activity value of said composition; a calculation unit which calculates the survival cell count of said strain contained in said composition after said storage period, by substituting the storage period of the composition containing said strain, the viable cell count of said strain contained in said composition at the initiation of storage, the storage temperature of said composition, and the water activity value of said composition, presented by said information on conditions for calculating the survival cell count, input of which has been received by said input receiver, into the following equation; and an output instruction unit which instructs to output information indicating the survival cell count of said strain contained in said composition after said storage period, which has been calculated by said calculation unit, Log 10 n t = Log 10 n 0 - t × EXP A T × T + B T w + C T × T + D T t: storage period (days) × 1/30 n t: survival cell count (CFU/g) of said strain contained in said composition after the storage period t (days) no: viable cell count (CFU/g) of said strain contained in said composition at the initiation of storage T: storage temperature (°C) w: water activity value of the composition A T: experimentally determined coefficient specific to said strain B T: experimentally determined constant specific to said strain C T: experimentally determined coefficient specific to said strain D T: experimentally determined constant specific to said strain. an input receiver which receives an input of information on conditions for calculating the survival cell count, which presents a storage period of the composition containing said strain, a viable cell count of said strain contained in said composition at the initiation of storage, a storage temperature of said composition, and a water activity value of said composition; a calculation unit which calculates the survival cell count of said strain contained in said composition after said storage period, by substituting the storage period of the composition containing said strain, the viable cell count of said strain contained in said composition at the initiation of storage, the storage temperature of said composition, and the water activity value of said composition, presented by said information on conditions for calculating the survival cell count, input of which has been received by said input receiver, into the following equation; and an output instruction unit which instructs to output information indicating the survival cell count of said strain contained in said composition after said storage period, which has been calculated by said calculation unit, Log 10 n t = Log 10 n 0 - t × EXP A T × T + B T w + C T × T + D T t: storage period (days) × 1/30 n t: survival cell count (CFU/g) of said strain contained in said composition after the storage period t (days) no: viable cell count (CFU/g) of said strain contained in said composition at the initiation of storage T: storage temperature (°C) w: water activity value of the composition A T: experimentally determined coefficient specific to said strain B T: experimentally determined constant specific to said strain C T: experimentally determined coefficient specific to said strain D T: experimentally determined constant specific to said strain. t: storage period (days) × 1/30 n t: survival cell count (CFU/g) of said strain contained in said composition after the storage period t (days) no: viable cell count (CFU/g) of said strain contained in said composition at the initiation of storage T: storage temperature (°C) w: water activity value of the composition A T: experimentally determined coefficient specific to said strain B T: experimentally determined constant specific to said strain C T: experimentally determined coefficient specific to said strain D T: experimentally determined constant specific to said strain.