This invention relates to functional socks which provide appropriate and variable compression on the various parts of foot. The functional compressive socks of this invention comprise the parts including shin, calf, instep, toe, heel, and sole. The said socks are characterized by the fact that all those said parts are subject to appropriate compression by part, and in addition, the said parts of shin, calf, instep, and sole are knitted with high elasticity yarn as the elastic threads and the core yarn single covered with polyurethane based long staple or long staple copolymer fiber as the inner threads, while the said parts of toe and heel are knitted with the core yarn single covered with polyurethane based long staple or long staple copolymer fiber as the inner threads, in appropriate ratio set respectively by the characteristics of the part. According to this invention which utilizes high elasticity yarn and implements a multi-stage compressive knitting technology that can adjust the lateral tensile force of the elastic threads, the blood in foot is pressed bilaterally promoting the circulation, therefore, the socks which can prevent or even treat the varix or edema can be produced.