The turbulent structure and the growth rate of the supersonic double shear layer were investigated experimentally. Subsonic air was in parallel injected into Mach 1.78 airstream. In order to contort the spanwise vortex, two configurations of curved injector were used. A new optical measurement that employs schlieren technique and a Pitot pressure measurement were conducted. The optical measurement revealed the existence of the contarted spanwise vortex. In case that spanwise vortex is cantorted, the contorted part of the spanwise vortex is considered to behave like a vortex pair. The spanwise averaged shear layer thickness was estimated from Pitot pressure measurement. Only asymmetric curved injector was effective in increasing the spanwise averaged shear layer thickness. For asymmetric curved injector, vortex pairs of upper and lower shear layers, rotating in the same direction, were considered to induce rib structures.