Experimental results for the dielectric measurement of HCl-doped ice are presented. A dielectric low-frequency dispersion was observed at a lower frequency side than the intrinsic Debye dispersion and is discussed on the basis of the temperature dependence of the relaxation time and the dielectric strength. In HCl-doped ice showing crossover phenomena between ac and dc conductivities on temperature dependence, the relaxation time of the low-frequency dispersion is constant above the crossover temperature. It increases with decreasing temperature below the crossover temperature, but HCl-doped ice does not clearly show crossover between relaxation times of the Debye and the low-frequency dispersions on temperature dependence.