Labour-saving pruning shears comprises a pivot assembly to pivotally connect primary 20 and secondary 22 shear blades thereof. Two rivet members 35, 36 having pin gears 252, 262 are disposed between a gear surface 282 of a sector gear block 28 and a toothed wall 222 extending from the secondary shear blade, the rivets are abutted against an inner side edge of a limiting guide slot 322 extending from the primary shear blade. The gear surface is abutted against the toothed wall. When a force is applied to first and second handles 26, 34 to drive the pin gears of the adjacent two rivet members to engage and rotate, the sector gear block can be rotated to move along the toothed wall, and the two rivet members are moved to limiting positions in the limiting guide slot, and a pivot assembly 24, 326, 224, 244 is rotated, so as to make the primary shear blade and the secondary shear blades perform an opening or closing operation.
