A package structure includes a first redistribution layer, a semiconductor die and a second redistribution layer. The first redistribution layer includes a first dielectric layer, first conductive elements, second conductive elements, a top dielectric layer and an auxiliary dielectric portion. The first conductive elements and the second conductive elements are disposed on the first dielectric layer with a first pattern density and a second pattern density respectively. The top dielectric layer is disposed on the first dielectric layer and covering a top surface of the second conductive elements. The auxiliary dielectric portion is disposed in between the first dielectric layer and the top dielectric layer, and covering a top surface of the first conductive elements. The semiconductor die is disposed on the first redistribution layer. The second redistribution layer is disposed on the semiconductor die, and electrically connected to the semiconductor die and the first redistribution layer.