To provide an ornament for producing the environment, enabling the temperature in a case for appreciation to be readily visualized.

The artificial ornament for producing the environment is used for producing the growing environment of an organism in the case 5 by being arranged in the case 5 for the appreciation. The ornament is formed so that the color of a part of the ornament body 4 may be changed, when the temperature in the case 5 for the appreciation reaches a temperature over the prescribed temperature range suitable for the breeding of the organism.