A developer supply kit detachably mountable to a developer supplying apparatus comprising a developer supply container and a developer accommodated therein, wherein the developer supply container includes, a developer accommodating portion accommodating the developer, a discharge opening for discharging the developer accommodated in the developer accommodating portion, a drive receiving portion to which a driving force is inputted from the developer supplying apparatus, and a pump portion operable so that an internal pressure of the developer accommodating portion alternately and repetitively changes between a pressure lower than a ambient pressure and a pressure higher than the ambient pressure, by the driving force received by the drive receiving portion, wherein the developer accommodated in the developer supply container includes toner containing binder resin material and a coloring material, the developer satisfies, 10≤E(mJ)≤80, 0.4≤Ea(mJ)≤2.0, where E is total energy when it is not aerated, and Ea is total energy when it is aerated.