procedure TForm1.ExcelToPDF(const AFilename: string);
Const
  XlTypePDF = 0;
  xlQualityStandard = 0;
  IncludeDocProperties = true;
  IgnorePrintAreas = false;
  LandscapeMode = 2;
var
  P: OleVariant;
begin
  P:= CreateOleObject('Excel.Application');
  try
    P.WorkBooks.Open(AFilename, 3);
    p.ActiveSheet.Pagesetup.Orientation := LandscapeMode;   orientation
    p.ActiveSheet.PageSetup.FitToPagesWide := 1;   // <-- not supported by automation object
    p.ActiveWorkbook.exportAsFixedFormat(xlTypePDF,
                                         AFilename,
                                         xlQualityStandard,
                                         IncludeDocProperties,
                                         IgnorePrintAreas );
  finally
    p.Quit;
  end;