Abstract: A developer supply apparatus for a processing head which develops an image exposure-formed on an electrophotographic film by a developer. The developer, which is stored in a bottle, is pumped up to a switching valve by the expansion and contraction of a bellows. The switching valve is selectively set in two positions, that is, a first position for returning the pumped developer to the bottle thereby stirring the developer, and a second position for delivering the developer to the processing head to effect development. The bellows is capable of supplying an amount of developer which is required for the processing head to effect one developing operation with one stroke, thus enabling development to be reliably carried out.