A bidirectional gate valve including: a blade (200) installed in a valve housing (100) having first and second passage holes (110, 120) to open/close the first and second passage holes (110, 120); a shaft (300) coupled to a lower portion of the blade (200); a first driving block (400) including: a first cylinder (410) which is provided under the valve housing (100) and into which the shaft (300) is inserted; a first piston (420) installed inside the first cylinder (410) and coupled to a lower portion of the shaft(300) to vertically move the shaft (300) according to pressure change inside the first cylinder (410).