A subelement (1) for an Nb3Sn-containing superconductor wire includes



an Sn-containing core (2),
an inner matrix (5) which includes Cu and surrounds the Sn-containing core (2),
a region (7) of mutually abutting Nb-containing rod elements (8, 30), which surrounds the inner matrix (5), where the Nb-containing rod elements (8, 30) are each configured with an Nb-containing core filament (9; 31) and a Cu-containing filament casing (10),
an outer matrix (6) which includes Cu and surrounds the region (7) of Nb-containing rod elements (8, 30). The Sn-containing core (2) has a core tube (3) into which an Sn-containing powder (4) has been introduced, the Sn-containing powder (4) being in a compacted state. This provides a subelement for an Nb3Sn-containing superconductor wire which cost-effectively yields an improved superconducting current carrying capacity.