A precursor to be used in manufacturing a Nb 3 Sn superconducting wire by an internal tin process, the precursor being a drawn wire product of a composite pipe, the composite pipe comprising: a composite wire group; a cylindrical barrier layer being disposed such that the cylindrical barrier layer surrounds the composite wire group to prevent permeation of tin; and a cylindrical protective layer covering an outer circumferential surface of the cylindrical barrier layer, wherein the composite wire group comprises: a plurality of tin wires each comprising at least one tin core being made of tin or a tin alloy, and a copper matrix which surrounds the at least one tin core; and a plurality of niobium wires each comprising a plurality of niobium cores being made of niobium or a niobium alloy, and a copper matrix which surrounds the plurality of niobium cores, the plurality of niobium wires being disposed such that each of the tin wires is surrounded by the niobium wires, wherein in a cross-sectional view, centers of gravity of cross-sectional regions of respective tin linear bodies each resulting from the plurality of tin wires are positioned to form a substantially planar lattice, characterized in that the composite wire group comprises titanium, and a content of titanium is greater than or equal to 0.38% by mass and less than or equal to 0.55% by mass, and an average distance from a center of gravity of a unit cell forming the substantially planar lattice to each center of gravity of the cross-sectional region of each of the tin linear bodies on lattice points of the unit cell is greater than or equal to 35 μm and less than or equal to 50 μm. the composite pipe comprising: a composite wire group; a cylindrical barrier layer being disposed such that the cylindrical barrier layer surrounds the composite wire group to prevent permeation of tin; and a cylindrical protective layer covering an outer circumferential surface of the cylindrical barrier layer, a composite wire group; a cylindrical barrier layer being disposed such that the cylindrical barrier layer surrounds the composite wire group to prevent permeation of tin; and a cylindrical protective layer covering an outer circumferential surface of the cylindrical barrier layer, wherein the composite wire group comprises: a plurality of tin wires each comprising at least one tin core being made of tin or a tin alloy, and a copper matrix which surrounds the at least one tin core; and a plurality of niobium wires each comprising a plurality of niobium cores being made of niobium or a niobium alloy, and a copper matrix which surrounds the plurality of niobium cores, the plurality of niobium wires being disposed such that each of the tin wires is surrounded by the niobium wires, wherein a plurality of tin wires each comprising at least one tin core being made of tin or a tin alloy, and a copper matrix which surrounds the at least one tin core; and a plurality of niobium wires each comprising a plurality of niobium cores being made of niobium or a niobium alloy, and a copper matrix which surrounds the plurality of niobium cores, the plurality of niobium wires being disposed such that each of the tin wires is surrounded by the niobium wires, wherein in a cross-sectional view, centers of gravity of cross-sectional regions of respective tin linear bodies each resulting from the plurality of tin wires are positioned to form a substantially planar lattice, characterized in that the composite wire group comprises titanium, and a content of titanium is greater than or equal to 0.38% by mass and less than or equal to 0.55% by mass, and an average distance from a center of gravity of a unit cell forming the substantially planar lattice to each center of gravity of the cross-sectional region of each of the tin linear bodies on lattice points of the unit cell is greater than or equal to 35 μm and less than or equal to 50 μm. centers of gravity of cross-sectional regions of respective tin linear bodies each resulting from the plurality of tin wires are positioned to form a substantially planar lattice, characterized in that the composite wire group comprises titanium, and a content of titanium is greater than or equal to 0.38% by mass and less than or equal to 0.55% by mass, and an average distance from a center of gravity of a unit cell forming the substantially planar lattice to each center of gravity of the cross-sectional region of each of the tin linear bodies on lattice points of the unit cell is greater than or equal to 35 μm and less than or equal to 50 μm.