Abstract: The invention is related to a line post insulator suitable for overhead lines of a higher voltage value than 1000 V. One of the practical examples of the line post insulator is equipped with a swinging stirrup placed in the insulator cap. In the swinging stirrup there is a tapered hole narrowing downwardly and holding clamping jaws. The clamping jaws are constructed so that they fit into the tapered hole. Another practical example of the line post insulator is suitable for fixing a conductor and/or a tie wire. In the insulator cap of this line post insulator a slot is formed narrowing in one axial direction of the conductor or the tie wire. In the narrowing slot above the conductor or the tie wire, a tapered clamping jaw is placed into the slot. In the slot there is a clamping jaw with parallel side edges placed under the conductor or the tie wire.