A water supply valve cartridge in which a flow rate control rotary disk has a reduced size, so that surface friction between the flow rate control rotary disk and a flow rate control fixed disk is minimized, thus improving manipulation efficiency of the water supply valve while opening or closing the valve, and which does not sensitively respond to flatness allowance due to the reduced size of the rotary disk, thus executing stable opening and closing operation. The flow rate control fixed disk (140) has water discharge holes (142). The flow rate control rotary disk (150) has a diameter to cover only the area around the water discharge holes (142), with a pair of flow rate control grooves (151) formed on the rotary disk (150) to open only the water discharge holes (142) during rotation.