the present invention provides a wet multi - plate clutch comprising a clutch case and hub disposed on a same axis , a first friction engagement element disposed in the clutch case , a second friction engagement element disposed on the hub , and a piston for applying an axial load to the first and second friction engagement elements , and wherein a recessed groove is formed in a surface of the piston opposing to the first and second friction engagement elements , and a wave spring is disposed within the recessed groove , and only a portion of the opposed surface at an outer diameter side or an inner diameter side of the recessed groove urges the respective friction engagement elements .