If you look at the data sheet for HIPER-TFS-2, pin 5 is the ground pin for the device, while pin 16 is the HD pin. Are you sure you are describing the right pins? It would be helpful if you posted a circuit for what you are trying to do.

thank PI-Wrench comment.
i was tried with schematic (attached photo)
But the voltage at pin 5 is increased as the same voltage at pin 16 (same 380V)

I applied a voltage than 12V to pin 5 and increased slowly the voltage to pin 16. But the voltage at pin 5 is increased as the same voltage at pin 16.

Thanks for the picture, now I understand your question.
The behavior you are seeing is normal. The high side driver inside the TFS-2 has an internal HV current source to power the high side electronics. If you power up the TFS-2 with an external 12V source and also apply voltage between HD and ground, the HS pin will float up, since the current source is referred to HS and the bottom switch is still disabled.
The VDDH graph you show in the picture is its response to an external voltage/current source. The VDDH pin has an internal shunt regulator that clamps the pin to ~12V, , which is why in the schematics you see this pin being fed through a resistor if it is getting additional power.