A similarity search method that causes a computer to perform a process, the process includes: first calculating, based on a plurality of record data, each of the record data including a plurality of feature quantities, normal hyperplane data representing a normal hyperplane, the normal hyperplane being a hyperplane dividing a feature quantity space, and a distance between a pair of divided areas having symmetry, second calculating, based on the plurality of record data and the normal hyperplane data, one-way hyperplane data representing at least one one-way hyperplane, the one-way hyperplane being a hyperplane dividing the feature quantity space, and a distance between a pair of divided areas having asymmetry, and converting, based on the normal hyperplane data and the one-way hyperplane data, query data including a plurality of feature quantities and the plurality of record data into respective binary strings.
