A method of manufacturing a bridge-type ball screw (1) with a bridge member (5) fit into a nut bridge window (6). The bridge member (5) has a linking groove (5a) with a rolling track that acts as a circulating path. After the bridge member (5) is fit into the nut bridge window (6), a cylindrical mandrel (8), with projections (9), is inserted into the nut (3). An upper die (10) restricts the upper surface of the bridge member (5) and is lowered while the nut (3) is held between the upper die (10) and the mandrel (8). A connection part is subject to plastic working by the projections (9) of the mandrel (8). The bridge member (5) is simultaneously deformed by the upper die (10) to secure the bridge member (5) into the nut bridge window (6).