The mechanical properties of a Peruvian small purse seine at a standard operation (tension of winch; F_w=367 kgw and velocity of winch; V_w=0.52m/s) and at an equilibrium condition of the force were determined. A 13 gross ton small purse seiner was utilized for the study. A standard size purse seine was constructed in accordance with the size of the fishing boat. The principal dimensions of the net are 123 fathoms of the float line and 13.3 fathoms of net height with a rectangular shape. Mechanical properties (tension; F, drag; D, velocity; v, and distance; s) were obtained during the pursing stage (suffix “1”); F₁=140 kgw, D₁=478 kgw, v₁=0.233m/S, and s₁=39.8 m, and the hauling stage (suffix “2”); F₂=367 kgw, D₂=289 kgw, v₂=0.363m/s, and s₂=24.3m. The results were confirmed to be reasonable by measured values of time lapse of a real fishing operation at sea. The results were further confirmed by examining the schematic diagram of tension. The drag coefficient obtained at the hauling stage showed K₂=7.58, while k=8 in the case of the trawl obtained by Koyama.