#!/usr/bin/perl

    use strict;
    use warnings;
    use Spreadsheet::WriteExcel;
    use Spreadsheet::ParseExcel;

    my $parser        = Spreadsheet::ParseExcel->new();
    my $in_workbook   = $parser->Parse('unicode_8859_7.xls');
    my $out_workbook  = Spreadsheet::WriteExcel->new('newfile.xls');
    my $out_worksheet = $out_workbook->add_worksheet();


    for my $in_worksheet ( $in_workbook->worksheets() ) {

        my ( $row_min, $row_max ) = $in_worksheet->row_range();
        my ( $col_min, $col_max ) = $in_worksheet->col_range();

        for my $row ( $row_min .. $row_max ) {
            for my $col ( $col_min .. $col_max ) {

                my $cell = $in_worksheet->get_cell( $row, $col );
                next unless $cell;

                $out_worksheet->write( $row, $col, $cell->value() );
            }
        }
    }


##</code><code>##

    ...
    use Spreadsheet::ParseExcel;
    use Spreadsheet::ParseExcel::FmtJapan;

    my $parser    = Spreadsheet::ParseExcel->new();
    my $formatter = Spreadsheet::ParseExcel::FmtJapan->new();

    my $in_workbook = $parser->Parse('unicode_8859_7.xls', $formatter);
    ...