Abstract: A centering device is provided which is adapted to be mounted on a running-in string for subsequent disposal in a well bore. Upper and lower companion supporting members having a plurality of circumferentially spaced openings therein and shoulders circumferentially extending around the uppermost interior of each of the supporting members are provided for receipt of circumferentially spaced and outwardly bowed springs having upper and lower ends overlying the lower portion of the exterior of the supporting members and extending inwardly through the openings. The springs have portions disposed in the openings with the upper and lower ends of the springs respectively engaging the upper and lower shoulder of the support members.