To increase heat capacity for absorbing frictional heat and attain miniaturization, in a multi-plate type friction engaging device.

Friction materials 41 of the outside of a diametral direction is stuck on internal tooth plates 34 of a multi-plate type friction engaging device 30 and friction plates 42 of the inside of a diameter direction are stuck on external tooth plates 35, 39. The outside friction materials 41 are friction engaged with the external tooth plates and the inside fiction materials 42 are friction engaged with the internal tooth plates and the friction heat generated by the friction engagement is absorbed by both external tooth plates 35, 39 and the internal tooth plates 34. Accordingly, the heat capacity of entire multi- plate type friction engaging device is increased and the friction material can be used for a long term. When the heat capacity is same as before, the arrangement length of the external tooth/internal tooth plates is shortened and the multi-plate type friction engaging device can be miniaturized and lightened.