Powershell venv only use envirnmental variables python, not python in venv directory (Windows)

I use vevn with python 3.6.8, pip 18.1.

I set powershell executionPolicy RemoteSigned,

create virtual environment with venv, refed to venv official site : (https://docs.python.org/3.6/library/venv.html)

and also activated according to powershell, used .<venv>\Scripts\activate.ps1

But when I execute 'pip list' command, it shows all packages installed in global, not in venv.

And when execute python - import sys - sys.prefix, to check python directory, I can find, powershell venv uses environmental variables python.

Of course, run it on cmd in same way, it works correctly. pip list shows

The pip list shows only packages installed in venv, and sys.prefix is python in venv directory.

Does anyone know why it works like this?

Powershell works correctly like cmd