To reveal the causes of infrared absorption in the wavelength region between electronic and lattice absorptions, we measured the temperature dependence of the absorption coefficient of p-type low-resistivity (sim 10^2~ Omega mathrm{cm}) CdZnTe crystals. We measured the absorption coefficients of CdZnTe crystals in four wavelength bands (lambda =6.45, 10.6, 11.6, 15.1~mu m) over the temperature range of T=8.6-300 K with an originally developed system. The CdZnTe absorption coefficient was measured to be alpha =0.3-0.5 mathrm{cm}^{-1} at T=300 K and alpha =0.4-0.9 mathrm{cm}^{-1} at T=8.6 K in the investigated wavelength range. With an absorption model based on transitions of free holes and holes trapped at an acceptor level, we conclude that the absorption due to free holes at T=150-300 K and that due to trapped-holes at T<50 K are dominant absorption causes in CdZnTe. We also discuss a method to predict the CdZnTe absorption coefficient at cryogenic temperature based on the room-temperature resistivity.