diff --git a/cmd/1pl/main.go b/cmd/1pl/main.go
index 2b1e5ed0..5f74cb88 100644
--- a/cmd/1pl/main.go
+++ b/cmd/1pl/main.go
@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"context"
 	"errors"
+	"flag"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -12,7 +13,6 @@ import (
 	"os/signal"
 	"strings"
 
-	"github.com/spf13/pflag"
 	"golang.org/x/crypto/ssh/terminal"
 
 	"github.com/ichiban/prolog"
@@ -25,8 +25,8 @@ var Version = "1pl/0.1"
 
 func main() {
 	var verbose bool
-	pflag.BoolVarP(&verbose, "verbose", "v", false, `verbose`)
-	pflag.Parse()
+	flag.BoolVar(&verbose, "v", false, `verbose`)
+	flag.Parse()
 
 	oldState, err := terminal.MakeRaw(0)
 	if err != nil {
@@ -99,7 +99,7 @@ func main() {
 		return k(env)
 	})
 
-	for _, a := range pflag.Args() {
+	for _, a := range flag.Args() {
 		b, err := ioutil.ReadFile(a)
 		if err != nil {
 			log.Panicf("failed to read %s: %v", a, err)
diff --git a/go.mod b/go.mod
index a81ce553..cbd42b79 100644
--- a/go.mod
+++ b/go.mod
@@ -5,7 +5,6 @@ go 1.16
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/kr/pretty v0.1.0 // indirect
-	github.com/spf13/pflag v1.0.5
 	github.com/stretchr/objx v0.1.1 // indirect
 	github.com/stretchr/testify v1.7.0
 	golang.org/x/crypto v0.0.0-20201016220609-9e8e0b390897
diff --git a/go.sum b/go.sum
index 5ee2d29f..477e0a5b 100644
--- a/go.sum
+++ b/go.sum
@@ -8,8 +8,6 @@ github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
-github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1 h1:2vfRuCMp5sSVIDSqO8oNnWJq7mPa6KVP3iPIwFBuy8A=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=