The utility model belongs to the technical field of spanners and discloses a labor-saving spanner. The labor-saving spanner has the following main technical features: the spanner comprises a spanner body with a driving end and a handgrip, wherein a lengthened handgrip is connected to the handgrip through a pin roll; the section of the lengthened handgrip is in a horizontally placed U shape, and the lengthened handgrip can rotate along the pin roll. In normal and construction and carrying, the lengthened handgrip can be rotated along the handgrip, so that the lengthened handgrip clamps against the handgrip, and the overall length is almost equivalent to the original length of the spanner, and thus the spanner is more convenient to use and carry; when a corroded threaded rod or slightly larger threaded rod is met, the lengthened handgrip can be rotated along the handgrip, and the acting force arm of the spanner is increased, and the torsion of the spanner is increased, such that the corroded threaded rod or slightly larger threaded rod is easy to unscrew, and the application range is larger.