diff --git a/internal/aria2/monitor.go b/internal/aria2/monitor.go
index fb55058d..3941963f 100644
--- a/internal/aria2/monitor.go
+++ b/internal/aria2/monitor.go
@@ -122,7 +122,7 @@ func (m *Monitor) Complete() error {
 			Name: fmt.Sprintf("transfer %s to %s", file.Path, m.dstDirPath),
 			Func: func(tsk *task.Task[uint64]) error {
 				defer wg.Done()
-				size, _ := strconv.ParseUint(file.Length, 10, 64)
+				size, _ := strconv.ParseInt(file.Length, 10, 64)
 				mimetype := mime.TypeByExtension(path.Ext(file.Path))
 				if mimetype == "" {
 					mimetype = "application/octet-stream"
diff --git a/internal/model/obj.go b/internal/model/obj.go
index 346f300d..43cd7c20 100644
--- a/internal/model/obj.go
+++ b/internal/model/obj.go
@@ -6,7 +6,7 @@ import (
 )
 
 type Obj interface {
-	GetSize() uint64
+	GetSize() int64
 	GetName() string
 	ModTime() time.Time
 	IsDir() bool
diff --git a/internal/model/object.go b/internal/model/object.go
index b8124fe8..37bc696a 100644
--- a/internal/model/object.go
+++ b/internal/model/object.go
@@ -5,7 +5,7 @@ import "time"
 type Object struct {
 	ID       string
 	Name     string
-	Size     uint64
+	Size     int64
 	Modified time.Time
 	IsFolder bool
 }
@@ -14,7 +14,7 @@ func (f Object) GetName() string {
 	return f.Name
 }
 
-func (f Object) GetSize() uint64 {
+func (f Object) GetSize() int64 {
 	return f.Size
 }