A secret sigmoid function calculation system in which t 0 and t 1 are assumed to be real numbers that satisfy t 0 < t 1 and g(x) is assumed to be a secure computable function, and the secret sigmoid function calculation system is configured with three or more secret sigmoid function calculation apparatuses and calculates, from a share [[x]] of an input value x, a share [[cr'(x)]] of a value of a sigmoid function for the input value x, the secret sigmoid function calculation system comprising: a first comparing means that generates a first comparison result [[c]] by [[c]] = less_than([[x]],t 1) from the share [[x]], wherein less_than([[x]],t) uses [[x]] as input and outputs [[[x < t]]], where [·] represents a predicate and t is a public value; a second comparing means that generates a second comparison result [[d]] by [[d]] = greater_than([[x]], t 0) from the share [[x]], wherein greater_than([[x]], t) uses [[x]] as input and outputs [[[x > t]]], where [•] represents a predicate and t is a public value; a first logical computation means that generates a first logical computation result [[e]] by [[e]] = not([[c]]) from the first comparison result [[c]], wherein not([[x]]) uses [[x]] as input and outputs [[¬x]]; a second logical computation means that generates a second logical computation result [[k]] by [[k]] = and([[c]], [[d]]) or [[k]] = mul([[c]], [[d]]) from the first comparison result [[c]] and the second comparison result [[d]], wherein and([[x]], [[y]]) uses [[x]] and [[y]] as input and outputs [[and(x, y)]], and wherein mul([[x]], [[y]]) uses [[x]] and [[y]] as input and outputs [[x×y]]; and a function value calculating means that calculates the share [[σ'(x)]] by [[cr'(x)]] = mul([[k]], [[g(x)]])+[[e]] from the share [[x]], the first logical computation result [[e]], and the second logical computation result [[k]], wherein the function g(x) is g(x) = ax+b, where a and b are real numbers, and the values of a, b, t 0, and t 1 are determined by the range of x for which the value of the sigmoid function is to be calculated. t 0 and t 1 are assumed to be real numbers that satisfy t 0 < t 1 and g(x) is assumed to be a secure computable function, and the secret sigmoid function calculation system is configured with three or more secret sigmoid function calculation apparatuses and calculates, from a share [[x]] of an input value x, a share [[cr'(x)]] of a value of a sigmoid function for the input value x, the secret sigmoid function calculation system comprising: a first comparing means that generates a first comparison result [[c]] by [[c]] = less_than([[x]],t 1) from the share [[x]], wherein less_than([[x]],t) uses [[x]] as input and outputs [[[x < t]]], where [·] represents a predicate and t is a public value; a second comparing means that generates a second comparison result [[d]] by [[d]] = greater_than([[x]], t 0) from the share [[x]], wherein greater_than([[x]], t) uses [[x]] as input and outputs [[[x > t]]], where [•] represents a predicate and t is a public value; a first logical computation means that generates a first logical computation result [[e]] by [[e]] = not([[c]]) from the first comparison result [[c]], wherein not([[x]]) uses [[x]] as input and outputs [[¬x]]; a second logical computation means that generates a second logical computation result [[k]] by [[k]] = and([[c]], [[d]]) or [[k]] = mul([[c]], [[d]]) from the first comparison result [[c]] and the second comparison result [[d]], wherein and([[x]], [[y]]) uses [[x]] and [[y]] as input and outputs [[and(x, y)]], and wherein mul([[x]], [[y]]) uses [[x]] and [[y]] as input and outputs [[x×y]]; and a function value calculating means that calculates the share [[σ'(x)]] by [[cr'(x)]] = mul([[k]], [[g(x)]])+[[e]] from the share [[x]], the first logical computation result [[e]], and the second logical computation result [[k]], wherein the function g(x) is g(x) = ax+b, where a and b are real numbers, and the values of a, b, t 0, and t 1 are determined by the range of x for which the value of the sigmoid function is to be calculated. a first comparing means that generates a first comparison result [[c]] by [[c]] = less_than([[x]],t 1) from the share [[x]], wherein less_than([[x]],t) uses [[x]] as input and outputs [[[x < t]]], where [·] represents a predicate and t is a public value; a second comparing means that generates a second comparison result [[d]] by [[d]] = greater_than([[x]], t 0) from the share [[x]], wherein greater_than([[x]], t) uses [[x]] as input and outputs [[[x > t]]], where [•] represents a predicate and t is a public value; a first logical computation means that generates a first logical computation result [[e]] by [[e]] = not([[c]]) from the first comparison result [[c]], wherein not([[x]]) uses [[x]] as input and outputs [[¬x]]; a second logical computation means that generates a second logical computation result [[k]] by [[k]] = and([[c]], [[d]]) or [[k]] = mul([[c]], [[d]]) from the first comparison result [[c]] and the second comparison result [[d]], wherein and([[x]], [[y]]) uses [[x]] and [[y]] as input and outputs [[and(x, y)]], and wherein mul([[x]], [[y]]) uses [[x]] and [[y]] as input and outputs [[x×y]]; and a function value calculating means that calculates the share [[σ'(x)]] by [[cr'(x)]] = mul([[k]], [[g(x)]])+[[e]] from the share [[x]], the first logical computation result [[e]], and the second logical computation result [[k]], wherein the function g(x) is g(x) = ax+b, where a and b are real numbers, and the values of a, b, t 0, and t 1 are determined by the range of x for which the value of the sigmoid function is to be calculated.