<p>This developing cartridge (19) comprises: a developing frame (25) having a first side wall (47); a developing gear (77) and a gear mechanism (78) that are arranged on the outer side surface of the first side wall (47); a collar member (72) that covers at least a portion of the peripheral surface of the developing gear (77); and a gear holder (73) that receives the gear mechanism (78) together with the first side wall (47). The collar member (72) is formed of a material that has better slidability than the gear holder (73). Both the collar member (72) and the gear holder (73) are positioned in common with respect to a positioning part (60) provided on the first side wall (47).</p>
