To prevent dropping off of a coil spring and ensure a contraction stroke amount without relying upon a short stroke type shock absorber even when a coil spring of short free length is incorporated.

The offset mounting adapter of the shock absorber for the vehicle includes a first cylindrical part 10a having a size which can pass through a through-hole 60c provided on a chassis 60; a first flange part 10b having a size which cannot pass through the through-hole 60c and formed on a lower end side of the first cylindrical part 10a; a first projection part 10c formed on an upper end side inner peripheral surface of the first cylindrical part 10a and capable of being abutted on a level difference part 34 formed on a piston rod 32; a second cylindrical part 20a capable of inserting an upper end side of the first cylindrical part 10a; and a second projection part 20c formed on an inner peripheral surface of the second cylindrical part 20a and abutted on the upper end side end surface 10f of the first cylindrical part 10a. Length of the second cylindrical part 20a is made to length L1 that a thread chasing part 38 formed on a distal end of the piston rod 38 can be exposed at assembling.