In this study, spectral emission coefficients of CF4 /O2 inductively coupled plasma were measured with a multichannel spectrometer with 34 lines of sight placed at the sides of the chamber. The horizontal distribution of spectral emission coefficients was obtained by spectral tomographic calculations based on a constrained regularization method. From the optical emission line spectra, the excited-level number densities of fluorine atoms 3 p^4 ^4D[7/2]^O and 3p^2 ^2P[3/2]^O were determined. The position distribution of electron temperature was diagnosed assuming corona equilibrium. The effect of chamber structure and equipment parameters on the position distribution of electron temperature is discussed.