Absolute optical oscillator strength density and double differential cross section spectra of CO below 120 eV are determined by fast electron impact. Some peaks above the first ionization threshold stand out as the momentum transfer square K2 increases. The doubly excited Rydberg states converging to C 2∑+, D 2Π, and F 2Π states of CO+, respectively, are confirmed in our spectra. Another peak at around 32eV is assigned to the transition of (3σ)-1(2π)1 1Π← X1∑+.