The positions in a text in which partial character strings in a pattern appear are efficiently detected. A partial-character-string position detecting device 1 takes inputs of a secret text [t] of a text t, a secrete text of a pattern p, a secret text of a vector c, and a secret text of a matrix E and outputs a secret text of a matrix H. A first matrix generating part 20 generates a secret text of a matrix F, in which F[i][j]=E[i][j+i mod n+1] (where it is assumed that E[i][n]=¬c[i]). A second matrix generating part 30 generates a secret text of a matrix F′, in which F[i][j]=1 is set if c[i]=0 or if c[i]=1 and F[k][j]=1 for every k that is successively c[k]=1, otherwise F[i][j]=0 is set, where k=i, . . . , n−1. A third matrix generating part 40 computes = ∧ ∧¬ to generate the secrete text .