To provide a biodegradable fishing line resistant to permanent deformation and having performance required as a fishing line and biodegradability and provide a method for efficiently producing the biodegradable fishing line.

The fishing line is a monofilament of a biodegradable synthetic resin having a tensile strength of ≥500 MPa, a knot strength of ≥350 MPa and a flexural recovery factor of ≥60%. The fishing line is produced by carrying out the melt-spinning, cooling, drawing and heat-setting of a biodegradable resin, winding the obtained monofilament, rewinding the wound monofilament in the form of a hank and subjecting the hank to relaxed treatment in a warm water of 35-65°C for 3-60 min.