In a developing device including a developing vessel for storing a developer, a first conveying passage, a second conveying passage, a first conveying member, a second conveying member and a developing roller, the first conveying member has a first rotary shaft and a first conveying blade formed on the periphery of the first rotary shaft, the first conveying blade has a first inner helical blade formed on the periphery of the first rotary shaft and a first outer helical blade arranged along the axis of the first rotary shaft and radially outside the outer periphery of the first inner helical blade, and the helical pitch of the first outer helical blade is specified to be shorter than the helical pitch of the first inner helical blade.