The present invention provides a crystal that has excellent oral absorption and can be obtained with particularly good reproducibility. Provided is a (R)-N-(1-(3-(cyclopentyloxy)phenyl)ethyl)-3-((2,4-dioxo-3,4-dih ydropyrimidine-1(2H)-yl)methoxy)propane-1-sulfonamide crystal.La presente invención proporciona un cristal que tiene absorción oral preferible y se puede obtener con una reproducibilidad particularmente preferible; se proporciona un cristal de (R)-N-(1-(3-(ciclopentiloxi)fenil)etil)--((2,4-dioxo-3,4-dihidrop irimidin-1(2H)-5 il)metoxi)propano-1-sulfonamida.