Implantation device for soft tissue markers and other implants

System and methods disclosed provide a device for inserting an implant with a medical function into body tissue. The device can include a channel passing through the implant, a cannulus with a channel sized to hold the implant, and a pusher with a channel and sized to be situated inside the channel of the cannulus behind the implant, and adapted to push the implant through a distal end of the cannulus into the tissue. The device can also include a restraining element that extends through the channel of the pusher and at least partly through the channel of the implant when they are so situated in the channel of the cannulus, which restrains the implant, but allows the implant to exit the distal end of the cannulus when the implant is pushed with a force small enough so as not to damage the function of the implant in the tissue.