A liquid withdrawing system comprising: a first container formed in a cylindrical shape along a first axis extending in a vertical direction, the first container having on a top surface an opening portion extending in a direction of the first axis and a recess; and a liquid withdrawing device attached to the opening portion, the liquid withdrawing device including: a cylindrical contact portion having a cylindrical shape, the cylindrical contact portion being in contact with an inner circumferential surface of the opening portion when the liquid withdrawing device is attached to the opening portion; an engaging claw connected to a lower end of the cylindrical contact portion, the engaging claw being elastically deformed inwardly when inserted along the inner circumferential surface of the opening portion and engaged with a lower end of the opening portion after passing through the opening portion; a cylindrical guide portion having a cylindrical shape and connected to a lower end of the engaging claw, the cylindrical guide portion being in contact with the inner circumferential surface of the opening portion when inserted along the inner circumferential surface; a siphon tube extending in a second axis direction and inserted toward the bottom surface of the first container; and a flow channel portion having a liquid flow channel connected to the siphon tube and a gas flow channel for leading a pressurizing gas supplied from an outside of the first container to an inner space of the first container, characterized in that the recess is provided at a position on a bottom surface of the container corresponding to the position of the opening portion on the top surface of the container, wherein the cylindrical guide portion guides a distal end of the siphon tube so that the distal end of the siphon tube is reliably inserted into the recess; and in that a second length in the second axis direction from a lower end of the cylindrical guide portion to a distal end of the siphon tube is shorter than a first length in the first axis direction from an upper end of the opening portion to the bottom surface of the first container, and a third length in the second axis direction from the engaging claw to the distal end of the siphon tube is longer than the first length such that when the engaging claw passes through the inner circumferential surface of the opening portion, a distal end of the siphon tube is in contact with the bottom portion of the recess. a cylindrical contact portion having a cylindrical shape, the cylindrical contact portion being in contact with an inner circumferential surface of the opening portion when the liquid withdrawing device is attached to the opening portion; an engaging claw connected to a lower end of the cylindrical contact portion, the engaging claw being elastically deformed inwardly when inserted along the inner circumferential surface of the opening portion and engaged with a lower end of the opening portion after passing through the opening portion; a cylindrical guide portion having a cylindrical shape and connected to a lower end of the engaging claw, the cylindrical guide portion being in contact with the inner circumferential surface of the opening portion when inserted along the inner circumferential surface; a siphon tube extending in a second axis direction and inserted toward the bottom surface of the first container; and a flow channel portion having a liquid flow channel connected to the siphon tube and a gas flow channel for leading a pressurizing gas supplied from an outside of the first container to an inner space of the first container, characterized in that the recess is provided at a position on a bottom surface of the container corresponding to the position of the opening portion on the top surface of the container, wherein the cylindrical guide portion guides a distal end of the siphon tube so that the distal end of the siphon tube is reliably inserted into the recess;