The invention relates to a coaxial coupling which comprises a male part (501) and a female part (502) and comprises a bypass valve (218) so that the female part (502) can be decoupled from the male part (501) while pressurized fluid passes through the female part (502). The nipple pipe (105) of the male part (501) pushes a spring-loaded valve (218) in the female part (502) over said rear holes (301) in the inner pipe (2) of the female part. The female part (502) has a rotatable locking sleeve (207), which is coupled to a sleeve (214) accommodating pins (213). The nipple pipe body (104) has helical grooves (100), wherein, upon coupling and rotation of the locking sleeve (207), the pins (213), through rotation of the pins (213), when they fall into the grooves (100), catch in the walls of the grooves (100) and cause the nipple pipe body (104) of the male part to be pulled into the female part (502), one end of the inner pipe (2) meets a relief valve (113) of the male part (501) and opens the relief valve (113), and pressurized oil is discharged against the valve of the female part (502) prior to continued opening of valves (115, 122) in the nipple pipe body (104).