diff --git a/format/format.go b/format/format.go
index 3fc3bdd..7be3ed0 100644
--- a/format/format.go
+++ b/format/format.go
@@ -436,11 +436,16 @@ func (f *fumpter) applyPre(c *astutil.Cursor) {
 				}
 			}
 			// If none of the comment group's lines look like a
-			// directive or code, add spaces, if needed.
+			// directive or code, add or remove spaces, as appropriate.
 			for _, comment := range group.List {
 				body := strings.TrimPrefix(comment.Text, "//")
 				r, _ := utf8.DecodeRuneInString(body)
-				if !unicode.IsSpace(r) {
+				if unicode.IsSpace(r) {
+					body = strings.TrimLeftFunc(body, unicode.IsSpace)
+					if rxCommentDirective.MatchString(body) {
+						comment.Text = "//" + body
+					}
+				} else {
 					comment.Text = "// " + body
 				}
 			}
diff --git a/testdata/script/comment-spaced.txtar b/testdata/script/comment-spaced.txtar
index aac33b1..caa8263 100644
--- a/testdata/script/comment-spaced.txtar
+++ b/testdata/script/comment-spaced.txtar
@@ -32,6 +32,8 @@ package p
 
 //noinspection foo,bar
 
+// directive:withleadingspace
+
 //not actually: a directive
 
 //https://just.one/url
@@ -99,6 +101,8 @@ package p
 
 //noinspection foo,bar
 
+//directive:withleadingspace
+
 // not actually: a directive
 
 // https://just.one/url