diff --git a/mackerel-plugin-snmp/README.md b/mackerel-plugin-snmp/README.md
index 801ae6b9..be550abc 100644
--- a/mackerel-plugin-snmp/README.md
+++ b/mackerel-plugin-snmp/README.md
@@ -7,7 +7,7 @@ SNMP V2c custom metrics plugin for mackerel.io agent.
 can specify multiple metric-definitions in the form of `OID:NAME[:DIFF?][:STACK?]` args.
 
 ```shell
-mackerel-plugin-snmp [-name=<graph-name>] [-unit=<graph-unit>] [-host=<host>] [-community=<snmp-v2c-community>] [-tempfile=<tempfile>] 'OID:NAME[:DIFF?][:STACK?]' ['OID:NAME[:DIFF?][:STACK?][:COUNTER?]' ...]
+mackerel-plugin-snmp [-name=<graph-name>] [-unit=<graph-unit>] [-host=<host>] [-port=<port>] [-community=<snmp-v2c-community>] [-tempfile=<tempfile>] 'OID:NAME[:DIFF?][:STACK?]' ['OID:NAME[:DIFF?][:STACK?][:COUNTER?]' ...]
  
 ```
 
diff --git a/mackerel-plugin-snmp/lib/snmp.go b/mackerel-plugin-snmp/lib/snmp.go
index e6351fa4..725b57c9 100644
--- a/mackerel-plugin-snmp/lib/snmp.go
+++ b/mackerel-plugin-snmp/lib/snmp.go
@@ -23,6 +23,7 @@ type SNMPPlugin struct {
 	GraphName        string
 	GraphUnit        string
 	Host             string
+	Port             uint16
 	Community        string
 	Tempfile         string
 	SNMPMetricsSlice []SNMPMetrics
@@ -33,6 +34,7 @@ func (m SNMPPlugin) FetchMetrics() (map[string]interface{}, error) {
 	stat := make(map[string]interface{})
 
 	gosnmp.Default.Target = m.Host
+	gosnmp.Default.Port = m.Port
 	gosnmp.Default.Community = m.Community
 	gosnmp.Default.Version = gosnmp.Version2c
 	gosnmp.Default.Timeout = time.Duration(30) * time.Second
@@ -93,6 +95,7 @@ func Do() {
 	optGraphUnit := flag.String("unit", "float", "Graph unit")
 
 	optHost := flag.String("host", "localhost", "Hostname")
+	optPort := flag.Uint("port", 161, "Port")
 	optCommunity := flag.String("community", "public", "SNMP V2c Community")
 
 	optTempfile := flag.String("tempfile", "", "Temp file name")
@@ -100,6 +103,7 @@ func Do() {
 
 	var snmp SNMPPlugin
 	snmp.Host = *optHost
+	snmp.Port = uint16(*optPort)
 	snmp.Community = *optCommunity
 	snmp.GraphName = *optGraphName
 	snmp.GraphUnit = *optGraphUnit
diff --git a/mackerel-plugin-snmp/test.sh b/mackerel-plugin-snmp/test.sh
index 22f3ec5c..bfab52b1 100755
--- a/mackerel-plugin-snmp/test.sh
+++ b/mackerel-plugin-snmp/test.sh
@@ -17,8 +17,7 @@ then
 fi
 
 image=local/test-$plugin
-# mackerel-plugin-snmp is disallowed --port option.
-port=161
+port=10161
 
 docker build -t $image testdata/
 
@@ -26,7 +25,7 @@ docker run --name "test-$plugin" -v $(pwd)/testdata/snmpd.conf:/etc/snmp/snmpd.c
 trap 'docker stop test-$plugin; docker rm test-$plugin; exit 1' 1 2 3 15
 sleep 10
 
-$plugin '.1.3.6.1.2.1.25.1.5.0:hrSystemNumUsers:0:0' '.1.3.6.1.2.1.25.1.6.0:hrSystemProcesses:0:0' '.1.3.6.1.4.1.8072.1.3.2.3.1.2.4.101.99.104.111:echo:0:0' | graphite-metric-test -f rule.txt
+$plugin -port $port '.1.3.6.1.2.1.25.1.5.0:hrSystemNumUsers:0:0' '.1.3.6.1.2.1.25.1.6.0:hrSystemProcesses:0:0' '.1.3.6.1.4.1.8072.1.3.2.3.1.2.4.101.99.104.111:echo:0:0' | graphite-metric-test -f rule.txt
 status=$?
 
 docker stop "test-$plugin"