Major countries (USA, EU, Japan) place more weight on the confusion criterion in judging design infringement or novelty. However, no country has adopted the pure confusion theory, and most countries have adopted the so-called modified confusion theory partially supplemented by the creation theory. In practice in the United States, design infringement or novelty tests are mainly about deception (confusion) of ordinary observers who are familiar with prior designs, but creative factors are taken into account by allowing prior designs to be considered. In the European Union, the criterion for confusion (discrimination) by the overall impression test is in principle, but by considering the 'informed user' who have some knowledge of the prior design and 'degree of freedom of designer,' the creative factors are also considered. In practice in Japan, since the similarity test in design is judged by “aesthetic sense perceived by the consumer’s eyes”, the main criterion for the similarity test depends on the consumer’s confusion, but creative factors not found in the preceding design are also considered. In the practice of the European Union and Japan, the final stage of the test is whether or not the aesthetic sense or impression is identical, but in the practice of the United States, the ordinary observer's deception is the criterion for judgment. Since most designs are made by newly combining and arranging various factors, it is necessary to observe such designs as a whole unified body. In this respect, the practice of the European Union and Japan, where the final criterion for similarity test is whether the overall aesthetic or impression is common, seems reasonable.