Compatibility summary
You will need a travel adapter in Argentina; plug types used there differ from Japan. Voltage differs by more than 20% — a voltage converter may be needed for some appliances.
Plug comparison
Japan plug types: A B
Argentina plug types: C I
There is no common plug type between Japan (A B) and Argentina (C I). You need a travel adapter.
Voltage comparison
Japan: 100V, 50Hz
Argentina: 220V, 50Hz
Voltage converter recommended (Japan 100V vs Argentina 220V).