The absorption spectra of CO2 have been studied within 1 mm region with the spectral resolution of 0.02 cm-1 under thermal excitation of molecules at temperatures from 300 to 1350 K and excitation by an electric discharge. A highly sensitive intracavity laser spectrometer based on neodimium-dopted glass laser was used in the experiment. New vibrational-rotational bands due to transitions from the (01101) highly excited vibrational state have been recorded. Spectroscopic constants for high vibrational states of CO2 have been determined.