To provide a holder for a thermometer inspection vessel not affected by a shape of a temperature sensor, and capable of securing safety for a worker.

This holder 2 is applied to the thermometer inspection vessel 1 used for a comparison calibration test for a thermometer 9. The holder is insertedly held in the inspection vessel to make its bottom wall 25 close to a heating medium 15 in the inspection vessel. An insertion hole 26 into which the thermometer 9 is insertedly held is formed in the bottom wall of the holder. A height adjusting screw 24 is provided in a flange part 22 in an upper part of the holder to allow advance and retreat along a vertical direction. A lower end part of the adjusting screw is brought into contact with a stepped part 18 of an upper opening of the inspection vessel to hold the holder to the inspection vessel. A position of the holder with respect to the vessel is adjusted vertically by adjusting the screw.