A developing device including: a developer container having a first transport passage and a second transport passage arranged substantially parallel to each other, the developer container containing developer containing toner; a developer carrier rotatably supported on the developer container, the developer carrier carrying, on a surface thereof, the developer inside the second transport passage; a first stirring/transporting member composed of a rotary shaft and a transport blade formed on a circumferential surface of the rotary shaft, the first stirring/transporting member stirring and transporting the developer inside the first transport passage; a second stirring/transporting member stirring and transporting the developer inside the second transport passage in a direction opposite to the first stirring/transporting member; a first developer passing portion through which the developer is delivered from the first transport passage to the second transport passage; and a second developer passing portion through which the developer is delivered from the second transport passage to the first transport passage, characterized in that the first stirring/transporting member includes, in a part thereof facing the first developer passing portion, a paddle portion which is devoid of the rotary shaft and is surrounded by the transport blade, which is located at a most downstream-side end with respect to the developer transport direction, two first ribs (51a, 51b), which extend from the transport blade parallel to the rotary shaft, and a second rib, which couples together respective end parts of the first ribs (51a, 51b) and which extends perpendicularly to the rotary shaft, the rotary shaft being connected to a face of the second rib facing away from a face thereof to which the first ribs (51a, 51b) are coupled. a developer container having a first transport passage and a second transport passage arranged substantially parallel to each other, the developer container containing developer containing toner; a developer carrier rotatably supported on the developer container, the developer carrier carrying, on a surface thereof, the developer inside the second transport passage; a first stirring/transporting member composed of a rotary shaft and a transport blade formed on a circumferential surface of the rotary shaft, the first stirring/transporting member stirring and transporting the developer inside the first transport passage; a second stirring/transporting member stirring and transporting the developer inside the second transport passage in a direction opposite to the first stirring/transporting member; a first developer passing portion through which the developer is delivered from the first transport passage to the second transport passage; and a second developer passing portion through which the developer is delivered from the second transport passage to the first transport passage, characterized in that the first stirring/transporting member includes, in a part thereof facing the first developer passing portion, a paddle portion which is devoid of the rotary shaft and is surrounded by the transport blade, which is located at a most downstream-side end with respect to the developer transport direction, two first ribs (51a, 51b), which extend from the transport blade parallel to the rotary shaft, and a second rib, which couples together respective end parts of the first ribs (51a, 51b) and which extends perpendicularly to the rotary shaft, the rotary shaft being connected to a face of the second rib facing away from a face thereof to which the first ribs (51a, 51b) are coupled. the transport blade, which is located at a most downstream-side end with respect to the developer transport direction, two first ribs (51a, 51b), which extend from the transport blade parallel to the rotary shaft, and a second rib, which couples together respective end parts of the first ribs (51a, 51b) and which extends perpendicularly to the rotary shaft, the rotary shaft being connected to a face of the second rib facing away from a face thereof to which the first ribs (51a, 51b) are coupled.