In order to find out transport models applicable to transport simulation of next generation helical devices, we compare the thermal diffusivities predicted by some theoretical models with the experimental data for present medium size helical devices (CHS (Compact Helical System), Heliotron E and W7AS (Wendelstein 7 AS)) with different magnetic configurations. We obtain the similar results in the three devices in spite of their difference of the magnetic configurations, except for the g-mode model.