The present invention provides: an I-type crystal of (E)-2-(7-trifluoromethyl chromane-4-ylidene)-N-((7R)-7-hydroxy-5,6,7,8-tetrahydronaphthalene-1-yl)acetamide having an excellent TRPV1 antagonistic activity； a medication and a medication composition containing said crystal； and a method for producing said crystal. The present invention provides an I-type crystal of (E)-2-(7-trifluoromethyl chromane-4-ylidene)-N-((7R)-7-hydroxy-5,6,7,8-tetrahydronaphthalene-1-yl)acetamide that is excellent in at least one property selected from the group consisting of preservation stability, photostability, and thermodynamic stability, that is preferably obtainable with high reproducibility, in high yield, and in high purity, and that is useful as a crystal for bulk pharmaceuticals.
