This paper argues that the principal - the principal agency costs from the outset to find an agent has occurred, and the continuing process throughout the agency, agency costs should therefore be an appropriate extension of the meaning of that agency costs is to let an agent on behalf of the principal result of an act additional costs of this, agency cost, including: search costs - the cost of search for appropriate and effective agents, incentive cost - to encourage agents to take actions consistent with the principal objective of the cost, monitoring costs - and to take preventive measures to reduce the cost of the agent misconduct occurred, the opportunity cost - due to various constraints and develop optimal strategies can not be cost; non-controllable costs - not entirely under the contract the agent can not control the misconduct which led to the loss of the principal interests of the.