Provided is a method of producing hydroxyalkylcellulose microparticles, the method including generating a pulse shock wave, and supplying a hydroxyalkylcellulose aqueous solution to the pulse shock wave generation region, thereby crushing and drying the hydroxyalkylcellulose aqueous solution. According to the production method, hydroxyalkylcellulose microparticles having a volume-average particle size of at least 0.1 μm but less than 15 μm are obtained. By mixing the hydroxyalkylcellulose microparticles with a principal agent and subjecting the resulting mixture to a tablet compression, a solid preparation having excellent tensile strength and disintegration properties can be obtained.
