A developer conveying device, comprising: a housing including a first wall portion and a second wall portion which are a pair of wall portions (70B,70C); a developer conveyance path (74a,74b) extending between the pair of wall portions; and a conveying member (72,73) rotatably supported on the wall portions and configured to convey developer from one wall portion to the other, the conveying member including: a spiral member (721,731) formed by connecting spiral pieces, each forming one spiral turn, in a conveying direction of the developer and including a hollow interior defined by the connected spiral pieces; first and second shaft portions (726,727,736,737) arranged at opposite end parts of the spiral member, the first and second shaft portions (726,727,736,737) being respectively rotatably supported on the second and first wall portions (70C, 70B) and serving as a rotary shaft for the rotation of the conveying member; a breaking member (721J,731J) extending across the hollow interior in a direction intersecting with the conveying direction, first and second rib members (722,723,732,733) extending in the conveying direction and bridging adjacent ones of the spiral pieces of the spiral member (721,731), the first and second rib members (722,723,732,733) being arranged in parallel to face each other with the rotary shaft of the conveying member as a center; and first and second supporting members (724,725,734,735) arranged to face the wall portion and connecting respective end parts of the first and second rib members in the conveying direction and the first and second shaft portions (726,727,736,737); wherein the first and second shaft portions (726,727,736,737) project axially outward of the first conveying member from a central part of the first and second supporting members (724,725,734,735), and the conveying member (72,73) includes no shaft part between the first and second shaft portions (726,727,736,737). a housing including a first wall portion and a second wall portion which are a pair of wall portions (70B,70C); a developer conveyance path (74a,74b) extending between the pair of wall portions; and a conveying member (72,73) rotatably supported on the wall portions and configured to convey developer from one wall portion to the other, the conveying member including: a spiral member (721,731) formed by connecting spiral pieces, each forming one spiral turn, in a conveying direction of the developer and including a hollow interior defined by the connected spiral pieces; first and second shaft portions (726,727,736,737) arranged at opposite end parts of the spiral member, the first and second shaft portions (726,727,736,737) being respectively rotatably supported on the second and first wall portions (70C, 70B) and serving as a rotary shaft for the rotation of the conveying member; a breaking member (721J,731J) extending across the hollow interior in a direction intersecting with the conveying direction, first and second rib members (722,723,732,733) extending in the conveying direction and bridging adjacent ones of the spiral pieces of the spiral member (721,731), the first and second rib members (722,723,732,733) being arranged in parallel to face each other with the rotary shaft of the conveying member as a center; and first and second supporting members (724,725,734,735) arranged to face the wall portion and connecting respective end parts of the first and second rib members in the conveying direction and the first and second shaft portions (726,727,736,737); wherein the first and second shaft portions (726,727,736,737) project axially outward of the first conveying member from a central part of the first and second supporting members (724,725,734,735), and the conveying member (72,73) includes no shaft part between the first and second shaft portions (726,727,736,737). a spiral member (721,731) formed by connecting spiral pieces, each forming one spiral turn, in a conveying direction of the developer and including a hollow interior defined by the connected spiral pieces; first and second shaft portions (726,727,736,737) arranged at opposite end parts of the spiral member, the first and second shaft portions (726,727,736,737) being respectively rotatably supported on the second and first wall portions (70C, 70B) and serving as a rotary shaft for the rotation of the conveying member; a breaking member (721J,731J) extending across the hollow interior in a direction intersecting with the conveying direction, first and second rib members (722,723,732,733) extending in the conveying direction and bridging adjacent ones of the spiral pieces of the spiral member (721,731), the first and second rib members (722,723,732,733) being arranged in parallel to face each other with the rotary shaft of the conveying member as a center; and first and second supporting members (724,725,734,735) arranged to face the wall portion and connecting respective end parts of the first and second rib members in the conveying direction and the first and second shaft portions (726,727,736,737); wherein the first and second shaft portions (726,727,736,737) project axially outward of the first conveying member from a central part of the first and second supporting members (724,725,734,735), and the conveying member (72,73) includes no shaft part between the first and second shaft portions (726,727,736,737).