It is intended to provide a method of producing a solid preparation disintegrating in the oral cavity characterized by comprising mixing fine subtilaes containing a medicinal ingredient with an additive containing δ-mannitol and tableting the mixture； and a solid preparation disintegrating in the oral cavity produced thereby. This solid preparation disintegrating in the oral cavity has such a strength (hardness) as suffering from no defect even under stresses in transporting, packaging with the use of an automated packaging machine, taking out from a PTP and soon.
