diff --git a/report_network_map.php b/report_network_map.php
index 8d969366..34efffc5 100644
--- a/report_network_map.php
+++ b/report_network_map.php
@@ -288,6 +288,7 @@
                         $color = $safeDeviceColors[array_rand($safeDeviceColors)];
                     }
 
+                    $baseURI = rtrim($config->ParameterArray["InstallURL"], '/') . '/'; // control if InstallURL with "/"
                     $graphstr .= "\t".$tkeypair[0]." [shape=Mrecord,URL=\"".$baseURI
                             .'devices.php?DeviceID='.$tkeypair[0]."\",label=\""
                             .$devList[$dt][$tkeypair[0]]."\",color=".$color."];\n";