An operation device includes an operating portion to receive a push-in operation, a lessening member to lessen tilt movement of the operating portion associated with the push-in operation, a supporting portion to support the lessening member, a base portion on which the supporting portion is provided, and at least one placement portion that is provided on the base portion, includes a placing surface to place an end portion of the lessening member, and holds the lessening member on the base portion by the placing surface and the supporting portion in a preparation stage for assembling the operating portion to the base portion.