Infrared diode laser absorption spectroscopy (IRLAS) was established as the measurement method for the CF radical density. The absolute density of the CF radical and its pressure dependences were measured in DC pulsed CF_4/H_2 discharge plasma. Moreover, from the analysis of the decay parts of the observed transient absorption waveforms of the CF radical, the CF radical was shown to be removed mainly by a diffusion process in the present plasma, yielding the diffusion coefficients D(CF in H_2) and D(CF in CF_4).