The present disclosure provides a wet friction engaging device. The device includes: a plate group engaged with two connecting members and including two groups of friction plates housed in a plate housing chamber and alternately arranged in an axial direction with surfaces facing each other; and a piston configured to apply a pressing force to the plate group. The plate group is switched between an engaged state in which the friction plates are in close contact with each other, and a disengaged state in which the friction plates are separable from each other. One of end plates at respective ends of the plate group is a movable end plate movable in the axial direction, and the other is a stationary end plate immovable in the axial direction. The movable end plate is biased by a spring.