The present invention relates to improved promoters and utilization thereof, in particular to promoters which are improved so as not to undergo methylation in the course of constructing transformants, and utilization thereof. According to the present invention, the expression efficiency of a structural gene can be enhanced even in a plant, e.g. chrysanthemum, which has weak expression of the structural gene by a cauliflower mosaic virus 35S promoter which as been considered a high expression promoter for plants.