The dictionaries offer solutions (firs of all: policing, law enforcement, regulatory activities), but neither of them can express what it really means: an administrative activity aiming maintenance of public security. According to Géza Finszter “rendészet” means the branch of public administration which has the social mission to prevent dangers arisen due to illegitimate human behavior by application of legitime power to that an independent appearance of a policing power is necessary and also sufficient. In his opinion belongs also prosecution to this definition. The author presents this problem outlined in the title along these ideas.