An orally disintegrating tablet is obtained by dry tabletting a mixture of: hydroxyalkyl cellulose microparticles having a 50% particle size in the cumulative particle size distribution of more than or equal to 15 µm and less than 40 µm, and having a hydroxyalkyl group content of 40 to 80% by mass a main drug as a pharmaceutical ingredient and optionally, additives such as an excipient, a binder, a disintegrant, a lubricating agent, an agent for sustained release, a base material, a coloring agent, a pH adjusting agent, a pH buffer agent, a surfactant, a stabilizer, an acidulant, a flavoring agent, a fluidizing agent, a refreshing agent, a sweetener, a savoring component, and a sweetness intensifier.누적 입도 분포에 있어서의 50% 입자 지름이 15㎛ 이상 40㎛ 미만이고 또한 히드록시알킬기의 함유량이 40~80질량%의 범위에 있는 히드록시알킬셀룰로오스 미립자와, 의약성분으로서의 주약과, 필요에 따라, 부형제, 결합제, 붕괴제, 활택제, 서방화제, 기재, 착색제, pH조정제, pH완충제, 계면활성제, 안정화제, 산미료, 향료, 유동화제, 청량화제, 감미료, 조미료성분, 감미 증강제 등의 첨가제를, 건식 타정 성형하여, 구강내 붕괴정을 얻는다.
