Simultaneous measurements of thermal diffusion processes of electrons and phonons in 1T‐TiS2 and intercalation compounds MxTiS2 (M=Mn, Fe, Co, and Ni; x=0.1–1/3) have been made in the temperature range 78–280 K using a pulsed laser‐induced ‘‘transient thermoelectric (TTE)’’ or photodiffusion effect. The initial stage of the decay curves of TTE voltage observed solely in TiS2 gives the electron‐hole recombination times τr, from which capture cross sections are evaluated. At the second stage, two relaxation times (τf and τs) are observed in all crystals; the fast and slow components are associated with the intra‐ and intervalley scatterings through electron‐phonon interactions, respectively. The evaluation of the final stage yields the thermal diffusion coefficient DT and thermal conductivity κ of these materials. The effect of intercalation of the guest 3d metals on these quantities is qualitatively discussed.