To provide a sheet-like formulation freely soluble in the oral cavity, easy to swallow, and with its bitter taste of a basic drug controlled.

This is a sheet-like formulation formed out of a material that contains: a basic drug (A); a masking agent (B) containing a basic group containing compound (b1) and an anionic polymer (b2); water-soluble fine particles (C); and a nonionic water-soluble polymer (D). The water-soluble fine particles (C) are present in a dispersed state within the formulation.