diff --git a/src/file/csv/SsBuilder.php b/src/file/csv/SsBuilder.php
index 2783de9..c25cdc3 100644
--- a/src/file/csv/SsBuilder.php
+++ b/src/file/csv/SsBuilder.php
@@ -73,6 +73,10 @@ class SsBuilder extends AbstractBuilder {
     }
     if ($styleHeader) {
       $ws->getStyle("$nrow:$nrow")->getFont()->setBold(true);
+      $maxcol = count($row);
+      for ($ncol = 1; $ncol <= $maxcol; $ncol++) {
+        $ws->getColumnDimensionByColumn($ncol)->setAutoSize(true);
+      }
     }
   }