A dual-screw linear actuator includes a power drive unit including a gear set mounted in a holder frame thereof and a driver for rotating the gear set, a transmission mechanism including a sleeve coupled to and rotatable by the gear set, a tubular linkage rod mounted in and rotatable by the sleeve and having a first threaded connection portion and a second threaded connection portion respectively located at two opposite ends thereof, a first lead screw threaded into the first threaded connection portion and affixed to the holder frame for guiding movement of the tubular linkage rod forwardly/backwardly relative to the first lead screw upon rotation of the tubular linkage rod and a second lead screw threaded into the second threaded connection portion and movable forwardly/backwardly relative to the tubular linkage rod upon rotation of the tubular linkage rod.