The invention discloses a focal length adjusting apparatus for a VR device. The apparatus comprises a rotating wheel, a left cross-arm wheel, a right cross-arm wheel, a left folding-arm wheel, a right folding-arm wheel, a left vertical wheel arm and a right vertical wheel arm, wherein a wheel disc rotates the rotating wheel, the wheel disc drives the left cross-arm wheel and the right cross-arm wheel to rotate, the left cross-arm wheel and the right cross-arm wheel drive the left folding-arm wheel and the right folding-arm wheel to rotate, and the left folding-arm wheel and the right folding-arm wheel then respectively drive the left vertical wheel arm and the right vertical wheel arm to rotate in a vertical direction. Besides, the invention further provides a VR device. Back-and-forth adjustment of a front cover is realized through the focal length adjusting apparatus for the VR device. Compared to the prior art, the VR device provided by the invention is firm in structure, improves the internal structure of virtual reality goggles, saves space, reduces the volume, at the same time, also reduces the weight, and enables a user wearing the goggles to have better experience.