An unwinder device and a method for unwinding a reel of a web-like material are provided. The unwinder device comprises: unwinding members for simultaneously unwinding a first reel (B1) and a second reel (B2); a splicing device for splicing together a first web-like material (N1) coming from said first reel (B1) and a second web-like material (N2) coming from said second reel (B2); at least one accumulator member for accumulating the web-like material (N2) supplied from said second reel (B2) before splicing to the web-like material (N1) supplied from said first reel (B1), where the accumulator member is disposed on the downstream of an area for starting splicing between the first and second web-like materials, comprising a device of winding spindle for supporting and rotating each reel; a cutting-off device is disposed for each winding spindle, which cuts off the web=like material winding on the associated winding spindle after splicing the first web-like material to the second one.