Abstract: A cannula insertion needle projects from the "forward" end of a hollow handle. After use to start a cannula, the needle is released from the end of the handle and its sharp end retracted into the handle, beyond reach. Preferably the handle has an aperture big enough for the needle but too small for fingertips. In one preferred form of the invention, the needle rides in a carrier block that slides inside the handle. Initially the block is secured in the handle against the forward end, with the sharp end of the needle protruding outward through the aperture. A manually releasable latch holds the block in this position. The latch mechanism includes mutually interfering stop elements on the exterior of the block and interior of the handle. After the cannula is in place, the person using the device withdraws the needle from the patient and manually triggers the carrier-block latch by squeezing or rotating one of the stop elements out of engagement with the other.