To provide a low-cost and compact length adjuster for a protection sheathing of a control cable easily usable in a narrow place and limiting the number of components.

This length adjuster for the protection sheathing 2 of the control cable 3 is provided with a hollow body 4 having both ends opened for passing the control cable 3 therethrough, a hollow sheath pipe 6 positioned on an extension line of an axis X-X', having both open ends for passing the control cable 3, having a groove 7 for storing one end of the protection sheathing 2, and fitted to the body 4 so as to axially rotate in parallel to the axis X-X' or parallel move in the axial direction between the maximum extended position Emax and a contracted position R, a spring 10 interposed between the body 4 and the sheath pipe 6 and positioning the sheath pipe 6 in the extension position, and a parallel moving blocking means 15 for the sheath pipe movable from a block released state D, so-called free translation state, to a block state B by the axial rotation motion of the sheath pipe 6 to the body 4.