Orally disintegrating tablet containing hydroxyalkyl cellulose microparticles

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.