The CsI(Tl) electromagnetic calorimeter of the BELLE detector for the KEK B-factory is reported. The energy resolution for γʹs and electrons have been achieved to 2.2% for E=4–7 GeV. The mass resolutions of π° was measured to 4.9 MeV for γʹs. The energy linearity is ∼±1% for γʹs.
