A combination of secure texts of values “a”, “b” and “c” having a relationship c=ab is efficiently generated. A secure text generation part 12 generates secure texts [xi] of xi satisfying xi=f(ki), and secure texts [yi] of yi satisfying yi=g(ki), for i=0, . . . , m. A fragment generation part 13 generates εi decrypted from [xi]−[ai] and ρi decrypted from [yi]−[bi], for i=1, . . . , m, and calculates [ci]+εi[bi]+ρi[ai]+εiρi and generates secure texts [z1], . . . , [zm]; and A random number synthesizing part 14 generates a secure text [z0] using different values k0, . . . , km and secure texts [z1], . . . , [zm].