Medical device with resiliently retracting safety needle

A medical device for percutaneous or venous access for administering a fluid to a patient or sampling from a patient, comprising:

• a tubular body from which there projects a cannula supported at a distal end of a cannula holder, a proximal end of said cannula holder being attached to a tube in which said fluid can circulate, said cannula holder being able to move within said body of the medical device under a force of a resilient thrust element,
• a stop member of one piece with said body and able to impede said movement of the cannula holder being provided and activating means being provided to allow said movement associated with the body of the medical device acting together with activating counter-means of one piece with said cannula holder,
• wherein said cannula holder has a yielding part positioned between and coaxially joined to its said distal end and to said proximal end whereby said yielding part is in fluid communication with said distal end and with said proximal end, said yielding part being configured to allow said cannula holder, at the proximal end, to flex within the body of the medical device when said activating means are activated so as to separate said cannula holder from said stop member to allow axial movement of the cannula holder in the body of the medical device and disappearing retraction of the cannula into the body.