In our society, in which a great variety of risk business transaction are carried, the parties concerned require often untypical mortgage to the contraries to make such transaction easy and effective. According to this requirement, the contraries, members of corporation, should offer assets of their companies as an mortgage arbitrarily. Members, who dare to carry out risk transaction for excessively profitable business, are very likely to commit breach of corporational trust. Accordingly it comes to be very important issue, to what extent criminal law should intervene in attitude of counter partner involved in those cases. If members conducting affairs of business commit jointly breach of trust, they can be punished as accomplice each all, but it is disputable, whether counter partner without status as members can be punished as an accomplice under the same condition, namely the Act Control('Tatherrschaft' in german). Under the precondition of answering this question affirmatively, it becomes an issue to put meaning of the Act Control into shape. Related to what the Act Control means, its constituents, mainly division of execution as an objective condition, mutual connection of intention, should be analysed on after another. If counter partner without status as members can not be punished as accomplice because of lacking the necessary condition, another problem becomes to be posed, whether his conduct leave no room for being punished especially as assistance. Because he assists the principal, member of company, in a way of daily deal activity('alltaegliches Verhalten' in german), he can be probably not punished as assistance of trust breach. The decision concerned(supreme court 2005.10.8. adjudged 2005do4915 sentence) declared 'not guilty' because of lack of illegality based on social adequateness. Despite of proper conclusion, I doubt whether the restriction of the extent of assistance should be made at the second level of illegality, because the first level of elements of constitung the case("Tatbestandsmaessigkeit" in german) can restrict the extent of assistance, by means of normative restriction or objective imputation.