The present invention relates to a novel production method of a novel prostaglandin derivative or a pharmaceutically acceptable salt thereof useful as a medicament, and an intermediate therefor. According to the present invention, a production method of a novel prostaglandin derivative or a pharmaceutically acceptable salt thereof including a conversion step from a compound represented by the following formula 3 to a compound represented by the formula 1 can be provided: wherein each symbol is as defined in the DESCRIPTION.