First I use
Python 3.6.5
Python 2.7.14
and mac.
In my case, I just download module like numpy(for example, and other's same) when i use pip3 it said like..

and pip is same.
In python2, It working well...

How can I fix it?
It seems that pip3  refers to Python-2.7's pip module or any other version of Python-3 that you have installed on your machine. However, you can install packages directly using the intended Python version. You'd need to just use -m option.
python3.6 -m pip install numpy
Another option is to changing the source path that pip3 refers to. You can do this by finding the path of Python-3.6's pip and just bind it to pip3 alias.
 
    
    Find the absolute path of the python3 interpreter with a command like this:
$ which python3
/Library/Frameworks/Python.framework/Versions/3.6/bin/python
Your path may be something different, of course. Copy that line to your clipboard.
Edit the pip3 script, which was installed using incorrect interpreter. Something like this:
vi $(which pip3)
You might need to use sudo here, but try it first without.  The first line will be something like:
#!/Library/Frameworks/Python.framework/Versions/2.7/bin/python
Change it to the path found in the previous step, e.g.
#!/Library/Frameworks/Python.framework/Versions/3.6/bin/python
Save the pip3 file and exit. This should be sufficient to associate pip3 with the correct environment. Check and verify the result with pip3 --version.  Now pip3 install numpy should work as expected.
