CONNECTION-DISCONNECTION DEVICE AND DIFFERENTIAL DEVICE

A connection-disconnection device configured to switch between a connected state and a released state of a side gear and a coupling shaft, each supported by a case member so as to be rotatable relative to the case member. The connection-disconnection device has an input shaft coupled to the side gear so as not to be rotatable relative to the side gear, axial movement of the input shaft being restricted with respect to the side gear, a dog member coupled to the coupling shaft so as not to be rotatable relative to the coupling shaft and so as to be movable with respect to the coupling shaft in an axial direction, and a moving mechanism configured to move the dog member back and forth in the axial direction. Each of the input shaft and the dog member has an annular meshing portion that mesh with each other. The dog member has a collar provided on an outer peripheral side with respect to the meshing portion, the collar configured to receive a flow resistance of lubricating oil accommodated in the case member when the dog member is moved in the axial direction.