Yes Thomastkim you have reason, thanks for the logic! :D I'm no sleep good for a very days for this, now do you can help me to a get eager loading pls?

Save new Employee and attach department to pivot:

public function store(Request $request)
{
$employee=Employee::create([
'name'      => $request->get('name'),
'lastname'  => $request->get('lastname'),
'job'       => $request->get('job'),
]);
//$employee=Employee::find($employee->id);
$employee->departments()->attach($request->department_id);

Employee model with select a column:

public function departments()
{
$query= $this->belongsToMany('Tlc\Department')
->select(['name_department']);
return $query;
}

Employee Controller:

public function index()
{
$employees= Employee::with('departments')->get();

return view('employee.index', compact('employees'));
}

Employee View

@foreach($employees as $employee)
<tbody>
<td>{{$employee->id}}</td>
<td>{{$employee->name}}</td>
<td>{{$employee->lastname}}</td>
<td>{{$employee->job}}<td>
<td>{{$employee->departments}}</td>
@endforeach