A developing cartridge for an image forming apparatus comprising: a housing, which is configured to accommodate developer therein, the housing including: a first sidewall and a second sidewall, which is opposed to the first sidewall; a developing roller, which is received by the first sidewall and the second sidewall, and is rotatable about a first axis line; a coupling, which is disposed at the first sidewall, and is rotatable about a second axis line parallel with the first axis line, wherein the coupling is configured to transfer rotational force to the developing roller, the rotational force being input by a drive input part of the image forming apparatus, which is configured to advance and retreat, with respect to the first sidewall, in a direction along the second axis line, characterized by a moving member extending so that the moving member connects the first and second sidewalls (131, 132) and received so that the moving member can be moved along the advancing and retreating direction of the drive input part, wherein the moving member includes: a pushed part at the first sidewall, which is configured to be pushed toward the second sidewall by a pushing force from the drive input part, and an electrode part at the second sidewall, which is configured to apply developing bias to the developing roller, and wherein if the pushed part is pushed by the pushing force of the drive input part, the moving member moves toward the second sidewall, so that the electrode part protrudes more from the second sidewall than before the pushed part was pushed. a housing, which is configured to accommodate developer therein, the housing including: a first sidewall and a second sidewall, which is opposed to the first sidewall; a first sidewall and a second sidewall, which is opposed to the first sidewall; a developing roller, which is received by the first sidewall and the second sidewall, and is rotatable about a first axis line; a coupling, which is disposed at the first sidewall, and is rotatable about a second axis line parallel with the first axis line, wherein the coupling is configured to transfer rotational force to the developing roller, the rotational force being input by a drive input part of the image forming apparatus, which is configured to advance and retreat, with respect to the first sidewall, in a direction along the second axis line, characterized by a moving member extending so that the moving member connects the first and second sidewalls (131, 132) and received so that the moving member can be moved along the advancing and retreating direction of the drive input part, wherein the moving member includes: a pushed part at the first sidewall, which is configured to be pushed toward the second sidewall by a pushing force from the drive input part, and an electrode part at the second sidewall, which is configured to apply developing bias to the developing roller, and a pushed part at the first sidewall, which is configured to be pushed toward the second sidewall by a pushing force from the drive input part, and an electrode part at the second sidewall, which is configured to apply developing bias to the developing roller, and wherein if the pushed part is pushed by the pushing force of the drive input part, the moving member moves toward the second sidewall, so that the electrode part protrudes more from the second sidewall than before the pushed part was pushed.