The present invention relates to functional sports pants. According to the present invention, one or more pieces (10) are formed by cutting a portion of fabric sport pants (2). An interspace between adjacent pieces (10) and an interspace between a pants cut part and the piece (10) are sewn in a zigzag manner with a tearable sewing thread (12) having tensile strength relatively lower than that of a common thread in order to form tearable lines (6)(8) in a pattern. The tearable sewing thread (10) is formed by combining a tearable fiber thread (14) having tensile strength lower than that of a polyester fiber sewing thread with a soluble thread (16). After producing a sewing thread, the soluble thread (16) is dissolved to leave only the tearable fiber thread (14) on the tearable sewing thread (12), which joins the tearable lines (6)(8) with each other. The sports pants are torn along the tearable lines (6)(8) when an opponent player makes a foul play such as pulling the sports pants too much intentionally. Accordingly, a referee can immediately recognize a foul play.
