An elliptic curve scalar multiplication apparatus stores a prime number p and information of a first point, the prime number p defining a field of definition Fp, which defines a first curve, which is a Weierstrass form elliptic curve, and expressed as p=p0+p1c+ . . . +p1cn−1, (where c equals 2f and f is an integer equal to or larger than 1 that is units of breaking data into pieces in multiple-precision integer arithmetic executed by the elliptic curve scalar multiplication apparatus), calculates a Montgomery constant k0, work, and h1, executes doubling of a second point, which is calculated from the first point, by Montgomery multiplication that uses k0, work, and h1, adds a third point and fourth point, which are calculated from the first point, by Montgomery multiplication that uses k0, work, and h1; and calculates a scalar multiple of the first point, based on a result of the doubling and the addition.