We present the ALMA detection of the [O III] 88 um line and dust continuum emission in a Y-dropout Lyman break galaxy. This [O III] detection confirms the spectroscopic redshift of the LBG to be z = 8.3118 ± 0.0003, making this galaxy one of the furthest galaxies ever identified spectroscopically. The observed 850 um flux density corresponds to a total-infrared luminosity and dust mass found in typical infrared luminous galaxies. The inferred [O III]-to-infrared luminosity ratio is very low (~ 0.1%) and is comparable to local spirals or dusty starbursts even if the uncertainty in dust temperature is considered. The ultraviolet-to-FIR spectral energy distribution along with the [O III] flux suggests the presence of a moderately-evolved stellar component, implying that a formation epoch dates back to z ~ 11. Despite a large uncertainty, an analytic dust mass evolution model reproduces these physical properties including the dust mass in the galaxy age (~0.2 Gyr), suggesting rapid enrichment of heavy elements in the middle of the reionization era.