ONTW>create or replace procedure tst
  2  as
  3    l_variable varchar2(100);
  4    procedure inner
  5    ( p_variable in varchar2
  6    ) is
  7    begin
  8      dbms_output.put_line('In inner: '||p_variable);
  9    end;
 10  begin
 11    l_variable := 'Hi!';
 12    dbms_output.put_line('In outer: '||l_variable);
 13    inner(l_variable);
 14  end;
 15  /

Procedure created.

ONTW>exec tst
In outer: Hi!
In inner: Hi!

PL/SQL procedure successfully completed.