The present invention is directed to provide 17-cyclopropylmethyl-3,14.beta.-dihydroxy-4,.alpha.-epoxy-6.beta.-[N-methyl-trans-3-(3-furyl)acrylamido]morphinanhydrochloride consistent inquality after production and having high purity. A crystal of 17-cyclopropylmethyl-3,14.beta.-dihydroxy-4,5.alpha.-epoxy-6.beta.-[N-methyl-trans-3 -(3 -furyl)acrylamido] morphinanhydrochlorideincluding a A-form, B-form or C-form crystal thereof, and a process forproducing the sameare provided.