This paper describes the investigations of the characteristic about the sound generation of a nose flute experimentally. The nose flute is attached to the upper part of a container. If air is passed to a nose flute, sound will occur. The volume of a container is changed and the generated sound is measured. The natural frequencies of an experimental device are calculated and we confirm that it is in agreement with frequency of sound generated in experiment. We show that nose flute is a unique musical instrument with the point that a nose flute has only an edge part and uses people's mouth for a resonance body part. The frequencies of resonance sound can be calculated from the capacity in a mouth, the thickness and the area of an opening of a nose flute. When people play a nose flute, it is thought that only the first mode of vibration is used.