The uniaxial magnetic anisotropy field, H_k, and g-factor of a c-plane oriented CoPtCr alloy film was quantitatively evaluated by using Q-band (∼34 GHz) ferromagnetic resonance (FMR). An FMR signal with a high signal-to-noise ratio was successfully obtained by using a 2mm^φ-Macor holder, which achieves phase matching, a decrease in the background of the signal, and accurate alignment of the external field parallel to the film normal or in-plane. An external field was applied perpendicularly or horizontally to the film, and a single magnetic domain was maintained during the measurements. The measured FMR signals demonstrated that 1) the H_k and g-factor were simultaneously derived for CoPtCr films with Co 75-90 at.%, 2) the magnitude of H_k was supported by that obtained with a Torque magnetometer, and 3) the g-factor increased from 2.11 to 2.19 when Co content was decreased from 85 to 65 at.% and the Cr content was increased from 5 to 20 at.%.