Öz
A contractor must carry out the work in person or have it carried out under their own direction (TCO 471 III, s. 1). However TCO 471 III, s. 2 states that, if the contractor's personal characteristics are not important in the carrying out the work, they may have the work done by someone else. In our study, the circumstances under which the contractor is obliged to carrying out the work directly and in which cases they can have the work done under his own direction are examined. Also the conditions of transferring of the carrying out the work to the subcontractors are evaluated. Besides in cases where the contractor is required to carrying out the work directly, the results of using a subsidiary person are discussed. Within the framework of this legal relationship, the legal ways has been investigated that the owner can apply in case of the main contractor is not authorized to use the subcontractor. In addition, in cases where the main contractor transfers the carrying out the work to the subcontractor without the authorization, the liability of the subcontractor for the damage caused by the actions of the subcontractor and in cases where the main contractor transfers the carrying out the work to the subcontractor with the authorization, the liability of the main contractor for the damage caused by the actions of the subcontractor are examined.