A joining device for parts of furniture and furnishing accessories, including a casing or container body suitable for being inserted in a seat formed in one of the components of the item of furniture to be joined and provided with an expansion bushing externally projecting with respect to an open end of the casing or container body and suitable for engaging with a further seat of a further component of the item of furniture to be joined to the component wherein the casing or container body is inserted, the joining device which includes a cam mechanism for a linear and reciprocated motion of an actuation unit co-operating in an expansion deformation movement of the expansion bushing and in a backward and traction movement of the same expansion bushing, with the cam mechanism and the actuation unit housed in the casing or container body and actuated by a tool.