A description is given a device that has been designed for the measurement on internal conversion coefficients by simultaneous observation of electron and gamma spectra with lithium-drifted silicon and germanium detectors, respectively. Calibration of the device was made by use of several well-known internal conversion coefficients (Hg 203, Au 198, Cs 137, Bi 207, Cd 109 sources). Dependence of the efficiency of the germanium detector for full-energy absorption of gamma-rays has been determined. Application of the method to the determination of conversion coefficients of the 191-keV transition from Pt 197 decay and of the 346-keV transition from Pt 197m decay is described. The following results are obtained: Pt 197: 191 keV transition, ∊κ = 0.69 ± 0.07, K/ L = 5.2 ± 0.6. Pt 197m: 346 keV transition, ∊κ = 3.9 ± 0.4, K/ L = 1.8 ± 0.2.