To provide a spinneret for a core-sheath type flat conjugated fiber, for stably producing the core-sheath type flat conjugated fiber without unevenness in thickness of a sheath component with little unevenness in thickness in the minor axis direction of a core component, and spinning a fiber allowing sufficient utilization of characteristics essentially possessed by the core-sheath type flat conjugated fiber.

There is provided the spinneret for spinning the core-sheath type flat conjugated fiber in which the cross section of the yarn has a flat shape. The spinneret is obtained by making one core component polymer inflow from a constricted part where the flow channel cross-sectional area having the flat shape is reduced in a joining part in which the core component polymer and the sheath component polymer are joined and laminated to form a core-sheath stream, and providing a weir for making the other sheath component polymer inflow from the minor axis direction of the flat constricted part; or the spinneret is obtained by forming the constricted part into two cylindrical flow channels with a prescribed interval kept therebetween, and making the sheath component polymer inflow from the whole circumferential direction of the weir.