diff --git a/.gitignore b/.gitignore
index 8815dff..65c4e2c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,7 @@ data
 *.out
 out.txt
 *.test
+
+.wrangler
+node_modules
+package-lock.json
diff --git a/internal/pdf/lex.go b/internal/pdf/lex.go
index defd32f..61bd0e9 100644
--- a/internal/pdf/lex.go
+++ b/internal/pdf/lex.go
@@ -82,7 +82,7 @@ func (b *buffer) errorf(format string, args ...interface{}) string {
 	return fmt.Sprintf(format, args...)
 }
 
-func (b *buffer) reload() (bool, error) {
+func (b *buffer) reload() {
 	n := cap(b.buf) - int(b.offset%int64(cap(b.buf)))
 	n, err := b.r.Read(b.buf[:n])
 	if n == 0 && err != nil {
@@ -90,29 +90,20 @@ func (b *buffer) reload() (bool, error) {
 		b.pos = 0
 		if b.allowEOF && err == io.EOF {
 			b.eof = true
-			return false, err
+			return
 		}
-		fmt.Sprint(b.errorf("malformed PDF: reading at offset %d: %v", b.offset, err))
-		return false, err
+		panic(b.errorf("malformed PDF: reading at offset %d: %v", b.offset, err))
 	}
 	b.offset += int64(n)
 	b.buf = b.buf[:n]
 	b.pos = 0
-	return true, err
 }
 
-func (b *buffer) seekForward(offset int64) (err error) {
+func (b *buffer) seekForward(offset int64) {
 	for b.offset < offset {
-		rel, err := b.reload()
-		if err != nil {
-			return err
-		}
-		if !rel {
-			return err
-		}
+		b.reload()
 	}
 	b.pos = len(b.buf) - int(b.offset-offset)
-	return err
 }
 
 func (b *buffer) readOffset() int64 {
diff --git a/internal/pdf/page.go b/internal/pdf/page.go
index 37b1adc..492f53b 100644
--- a/internal/pdf/page.go
+++ b/internal/pdf/page.go
@@ -55,13 +55,21 @@ Search:
 }
 
 // NumPage returns the number of pages in the PDF file.
-func (r *Reader) NumPage() int {
-	return int(r.Trailer().Key("Root").Key("Pages").Key("Count").Int64())
+func (r *Reader) NumPage() (n int, err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			err = fmt.Errorf("failed to get number of pages: %v", r)
+		}
+	}()
+	return int(r.Trailer().Key("Root").Key("Pages").Key("Count").Int64()), nil
 }
 
 // GetPlainText returns all the text in the PDF file
 func (r *Reader) GetPlainText() (reader io.Reader, err error) {
-	pages := r.NumPage()
+	pages, err := r.NumPage()
+	if err != nil {
+		return nil, err
+	}
 	var buf bytes.Buffer
 	fonts := make(map[string]*Font)
 	for i := 1; i <= pages; i++ {
diff --git a/toukibo_parser_test.go b/toukibo_parser_test.go
index 195f8f6..b087fb3 100644
--- a/toukibo_parser_test.go
+++ b/toukibo_parser_test.go
@@ -179,3 +179,13 @@ func TestToukiboParser(t *testing.T) {
 		})
 	}
 }
+
+func TestBrokenToukibo(t *testing.T) {
+	for i := 1; i <= 3; i++ {
+		pdfFileName := fmt.Sprintf("testdata/broken/broken%d.pdf", i)
+		_, err := GetContentByPDFPath(pdfFileName)
+		if err == nil {
+			t.Fatal("should be error")
+		}
+	}
+}