PURPOSE: To provide a measuring instrument for a frozen ground which is capable of obtaining characteristic values of thermal matters, especially letent heat as an information on the frozen ground when informations on the frozen ground are reguired.

CONSTITUTION: A measuring cell 4 is pushed and inserted by the 1st pusher 3 from the surface of a ground in the center of the ground bottom part 2 of a fore 1. This pusher 3 is composed of a main hydraulic cylinder and a measuring cell is connected with the lower end of its piston rod. The 2nd pusher 5 composed of an auxiliary hydraulic cylinder is fitted to both sides of the lower end part of the pusher 3. And a rod measuring instrument 8 furnished with a thermal sensor 6 and a water pressure sensor 7 fitted to this pusher 5 is pushed and inserted into both sides of the ground bottom 2 of the fore 1 by the operation of the pusher 5 and the latent heat is obtained.