Provided are an alkyl cellulose excellent in formability when added even in a small amount and not causing marked delay in disintegration; a solid preparation comprising it; and a method for producing the solid preparation. More specifically, provided are an alkyl cellulose for use in tableting, the alkyl cellulose having a specific surface area of from 0.5 to 10.0 m2/g as measured by BET method and a solid preparation comprising the alkyl cellulose. Also provided is a method for producing the alkyl cellulose, comprising the steps of : bringing pulp into contact with an alkali metal hydroxide solution to obtain alkali cellulose, reacting the alkali cellulose with an etherifying agent to obtain a first alkyl cellulose, pulverizing the first alkyl cellulose, and depolymerizing the pulverized first alkyl cellulose through hydrolysis with an acid catalyst or through oxidative decomposition with an oxidant to obtain a second alkyl cellulose.