Provided is a pilot solenoid valve capable of bringing the strokes of a plunger to a necessary minimum and capable of achieving solenoid valve miniaturization and power saving. A pilot solenoid valve is provided with a diaphragm section, a primary side section, a secondary side section, a main valve, a back pressure chamber, a primary side auxiliary flow path, a secondary side auxiliary flow path, an auxiliary valve, and an auxiliary valve drive unit, wherein the secondary side auxiliary flow path is not formed in the main valve but rather is formed in the area around the main valve so as to bypass the main valve.