The problem of high-frequency conductivity of a thin cylindrical semiconductor wire has been solved by the kinetic method. The diffuse-specular mechanism of reflection of charge carriers from the inner surface of the wire has been considered. Calculations have been performed for an n-type (p-type) nondegenerate semiconductor with a standard spherically symmetric energy band. The ratio between the cross-section radius of the wire and the mean free path of charge carriers is assumed to be arbitrary.