which work on the axially extending part 17 of the retainer when the outer and inner rings engage and disengage are supported by the annular side plates 10 consequently the axially extending part 17 of the retainer 9 is prevented from moving in said directions thereby always keeping the sprag 3 which slidingly contacts the axially extending part 17 in a fixed position this permits easily designing a one way clutch best suited for transmitting the desired torque by spacing the sprags 3 at suitable intervals as shown in fig2 namely the number of the sprags can be increased or decreased according to the amount of torque involved by placing the sprag at every second section of the retainer as shown in fig2 at every third section and so on when fitting the annular side plate 10 the retainer 9 made of steel wire rod permits taking advantage of the elasticity thereof in addition many sprags can be inserted en bloc between the outer and inner rings all this results in easy and rapid assembly and therefore in low priced one way clutches this invention is by no means limited to the above described embodiments with reference to fig5 and 7 for example the retainer 9 9 39 or 9 34 may be disposed adjacent the inside of the outer ring 1 the sprag 3 may be turned upside down to turn the groove 12 toward the inner ring 2 further a compression spring urging outward may be fitted in the groove 12 too in this case the embodiment of fig7 and 8 is modified in such a manner that the recesses 18 are provided along the external boundary of the annular side plate 10 two annular garter.