A pipe-joining centering device aligns, with an axial center of one pipe, an axial center of another pipe when a spigot of the other pipe is to be inserted into a socket of the one pipe. The pipe-joining centering device includes a support member configured to support an end part of the spigot. The support member is tiltable in a pipe radial direction between an inner peripheral surface of the socket and an outer peripheral surface of the spigot. The pipe-joining centering device also includes a position adjustment member configured to tilt the support member in the pipe radial direction. The support member and the position adjustment member are supported on the inner peripheral surface of the socket.