A fluid sealing device and a pressure detector calibration device are provided to enable further reducing of errors between a sealing pressure and a set pressure in a fluid flow path.
The fluid sealing device includes a pressure sealing structure having a fluid inlet, a fluid outlet, and a fluid flow path formed therein, a temperature controller, a temperature detector, a pressure detector, an inlet-side on-off valve, an outlet-side on-off valve, a restriction part, a fluid supply device, a fluid sealing controller for sealing the fluid in the pressure sealing structure by controlling the fluid supply device, the inlet-side on-off valve, and the outlet-side on-off valve, wherein the fluid sealing controller opens the outlet-side on-off valve after increasing the pressure in the fluid sealing structure to a primary pressure higher than the set pressure, and closes the outlet-side on-off valve when a value detected from the pressure detector becomes a corrected set pressure by an error correction value corresponding to a temperature detected by the temperature detector at the set pressure.