To provide a gas transportation-storage tank enabling the detection of leakage of gas even when odorant cannot be uniformly added to gas itself.

The gas transportation-storage tank includes a pressure container 3 for storing gas, a cover body 7 provided over the outer peripheral face of the pressure container 3 via a space 5 for covering the pressure container 3, and a gas releasing device 9 provided on the cover body 7 and set to release the gas from the space 5 when gas pressure in the space 5 between the cover body 7 and the pressure container 3 becomes predetermined pressure. Odor gas is filled in the space 5, and a relationship among gas pressure P1 in the pressure container 3, gas pressure P2 in the space 5 and set pressure P3 for the gas releasing device 9 is set to be P1P3P2.