To provide a liquefied gas measuring device which reduces connecting parts by integrating each instrument, prevents leakage of liquefied gas, requires only a simple pressure test, and enables miniaturization of a metering device and an accurate correction of temperature.

The liquefied gas measuring device 6 is connected to some midpoint of piping, one end of which is connected to a liquid storage tank and the other end of which is connected to a filling nozzle. The device 6 outputs a flow rate signal from a flowmeter 26 provided inside a main body case 20. The case 20 is formed in such a manner that a main body inflow opening 7 having a strainer 21 is provided at one end and that a float chamber 22 having a main body discharge opening 8 is provided at the other end. The float chamber 22 is provided with a temperature sensor 28 and a float valve 23 which is located in an upper position and makes an upper opening opened when vapors flow in from the inflow opening 7. A metering mechanism equipped with the flowmeter 26 is provided below a descent position of a float 23a of the float valve 23. A discharge opening of the metering mechanism is connected to the discharge opening 8. A check valve 25 is provided on a side of the inflow opening 7.