Abstract: A hand-held safety utility knife having an elongated shaped handle within which a replaceable cutting blade is securely retained, wherein the knife assembly is also provided with a compression-extension spiral spring loaded retractable blade guard that is mechanically cooperative with the cutting blade of the knife and manually activated for retraction by depressing a compression-extension spiral spring loaded trigger thereby enabling cutting utility of the blade in use application, and upon manual trigger release after use application provides non-use safety locking of the guard with respect to the utility knife cutting blade.