A rotary machine comprising: a rotor disk including a plurality of slots; a plurality of blades mounted on an outer circumferential surface of the rotor disk, each of the blades having a root part inserted into an associated one of the slots in an axial direction; characterised by a retainer (1400, 1500, 1600) restraining axial movement of the plurality of blades, wherein the retainer (1400, 1500, 1600) comprises: - an inner fixing member (1410, 1510, 1610) inserted into a bottom of the slot, wherein the bottom of the slot is provided with an inner groove into which the inner fixing member (1410, 1510, 1610) is inserted, and the lower surface of the root part is provided with a first groove into which the inner fixing member (1410, 1510, 1610) is inserted, - an outer fixing member (1420, 1520, 1620) inserted into a lower surface of the root part to abut against the inner fixing member (1410, 1510, 1610), and - a spacer (1430, 1530, 1630) inserted between the outer fixing member (1420, 1520, 1620) and the bottom of the slot to prevent the outer fixing member (1420, 1520, 1620) from being separated, wherein the outer fixing member (1420, 1520, 1620) includes a body portion (1421, 1521, 1621) inserted into the root part and a support plate protruding from a side of the body portion (1421, 1521, 1621) in a lateral direction and bent to abut against an end of the spacer (1430, 1530, 1630). a rotor disk including a plurality of slots; a plurality of blades mounted on an outer circumferential surface of the rotor disk, each of the blades having a root part inserted into an associated one of the slots in an axial direction; characterised by a retainer (1400, 1500, 1600) restraining axial movement of the plurality of blades, wherein the retainer (1400, 1500, 1600) comprises: - an inner fixing member (1410, 1510, 1610) inserted into a bottom of the slot, wherein the bottom of the slot is provided with an inner groove into which the inner fixing member (1410, 1510, 1610) is inserted, and the lower surface of the root part is provided with a first groove into which the inner fixing member (1410, 1510, 1610) is inserted, - an outer fixing member (1420, 1520, 1620) inserted into a lower surface of the root part to abut against the inner fixing member (1410, 1510, 1610), and - a spacer (1430, 1530, 1630) inserted between the outer fixing member (1420, 1520, 1620) and the bottom of the slot to prevent the outer fixing member (1420, 1520, 1620) from being separated, - an inner fixing member (1410, 1510, 1610) inserted into a bottom of the slot, wherein the bottom of the slot is provided with an inner groove into which the inner fixing member (1410, 1510, 1610) is inserted, and the lower surface of the root part is provided with a first groove into which the inner fixing member (1410, 1510, 1610) is inserted, - an outer fixing member (1420, 1520, 1620) inserted into a lower surface of the root part to abut against the inner fixing member (1410, 1510, 1610), and - a spacer (1430, 1530, 1630) inserted between the outer fixing member (1420, 1520, 1620) and the bottom of the slot to prevent the outer fixing member (1420, 1520, 1620) from being separated, wherein the outer fixing member (1420, 1520, 1620) includes a body portion (1421, 1521, 1621) inserted into the root part and a support plate protruding from a side of the body portion (1421, 1521, 1621) in a lateral direction and bent to abut against an end of the spacer (1430, 1530, 1630).