To prepare a high-density activated carbon fiber sheet having excellent handleability, causing neither break nor crack in formation in post processing, in application, or the like, and to provide a method for producing the same.

This activated carbon fiber sheet is a sheet consisting essentially of an activated carbon fiber and a conjugate fiber comprising a high-melting polymer as a core component and a low-melting polymer as a sheath component. The activated carbon fiber is bonded to the sheath component by its fusion with the sheath component of the conjugate fiber. The activated carbon fiber sheet comprises 10-90 mass % of the activated carbon fiber and has 20-300 g/m2 weight and ≥0.10 g/cm3 density.