A needle device has a needle retraction mechanism that retracts the needle upon removing the device from the skin surface (either intentionally or unintentionally). Once the needle is retracted, the device is rendered inoperative. The needle can be further made inoperative by bending it when one attempts to reuse the device. In another embodiment, a needle opening formed in the base of the housing can be covered to render the needle inoperative when one attempts to reuse the device. In another embodiment, the needle device instead has a needle shield that automatically covers the needle after use.