Abstract: A semiconductor device includes an element mounting portion, suspending leads, a large number of inner leads, a semiconductor element, and insulating tapes. The element mounting portion is arranged at a central portion of a lead frame. The suspending leads support four corners of the element mounding portion from a peripheral portion of the lead frame. The large number of inner leads are formed toward the element mounting portion. The semiconductor element is mounted on the element mounting portion and has electrode portions connected to distal ends of the inner leads. Each of the insulating tapes has cut portions obtained by partially cutting two corners of both ends of a rectangle of each of the tapes near the element mounting portion and projection portions projected from two corners of the rectangle far from the element mounting portion and each having the same shape of each of the cut portions. The insulating tapes are adhered to the inner leads parallelly to four sides of the semiconductor element.