Fixator is a kind of medical device that is used for holding a medical instrument like trocar, on the skin of a patient during a surgery. It is available with an attachment that is ideal for releasable fixation of the device on the patient. It consists of an aperture through which the instrument is received. It helps in frictionally engaging the instrument in the fixation device wherein the attachment device encompasses a flexible sheet-like member as well as the aperture that is available with a related instrument having slot in the attachment device for radial insertion of the instrument. This kind of fixation device is suitable to be used in context with the instruments such as trocars with a wide range of external diameters.