Research in the relation between the viewers' attitudes to television programs and their opinions on crimes was carried out by means of questionnaires. The subjects were 744 junior and senior high school students from 12 to 18 years of age. The results were as follows: (a) Those who like police-thriller programs find various causes in the occurrence of crimes, and devise various counterplans. (b) Those who like police-thriller programs, historical dramas, and sports programs are inclined to find the causes of crimes in ‘the characters of criminal themselves’, but those who like culture programs, family dramas for young people, and popular song programs maintain that the causes of crimes are ‘environmental’ . (c) Those who like historical dramas, comic plays, sports programs, and family dramas for young people are inclined to expect ‘measures by athird party’ as conterplans to crimes, but those who like culture programs count on ‘self-knowledge’ of those concerned. (d) Through factor analysis, 11 actors, or special qualities, of images of criminals were found, and each of them was named as follows: wretched conditions of life, strange looks and dresses, lack of tenderness, weakness of will, simplicity, ostentatious behaviors, disappointment and deep grief, abnormal mind, restlessness, gloomy and reserved perverseness, and impudence. The more important among them are disappointment and deep grief, wretched conditions of life, strange looks and dresses, weakness of will, and gloomy and reserved perverseness. (e) Those who like police-thriller programs have the most varied images of criminals, but those who like sports programs, culture programs, and comic plays have the poorest images of them. (f) It can safely be said that police-thriller programs have various effects on viewers in forming the images of criminals and forming opinions on the causes of, and the counterplans to, crimes.