The present invention provides a type I crystal of (E)-2-(7-trifluoromethyl-chroman-4-ylidene)-N-((7R)-7-hydroxy-5,6,7,8-tetrahydronaphthalen-1-yl)acetamide having excellent TRPV1 antagonistic activity, a drug and a pharmaceutical composition containing this crystal, and a method for producing the crystal. The present invention provides a type I crystal of (E)-2-(7-trifluoromethyl-chroman-4-ylidene)-N-((7R)-7-hydroxy-5,6,7,8-tetrahydronaphthalen-1-yl)acetamide that is excellent in at least one feature selected from the group consisting of storage stability, photostability and thermodynamic stability, that can be preferably obtained with industrially high reproducibility, yield and purity, and that is useful as a crystal of an active pharmaceutical ingredient.
