The field-amplitude Hm and circular frequency ω dependent ac susceptibility, χ= χ′ -j χ″, of a hard superconducting cylinder with flux-flow type current-voltage characteristic is calculated. A remarkable feature of the resultant χ (Hm, ω) is that both the maximum χ″, χm″, and d lg Hm (χm″) d lg ω increase with increasing ω. This behavior is observed in actual Bi-2223/Ag tapes and Y Ba2 Cu3 O7-δ -coated conductors. Our result provides a useful tool to study the intergranular critical state in high-temperature superconductors. © 2005 American Institute of Physics.