The invention provides a locking device capable of being opened inside and outside. The locking device comprises a folding plate and an L-shaped hanging plate, wherein a rotary interlocking mechanism comprises a rotating shaft seat and a rotating shat arranged in the rotating shaft seat, a hand shank which can rotate the rotating shaft is arranged at the upper end of a pin axle of the rotating shaft, and fixed on the pin axle of the rotating shaft through split pins; a hand shank is arranged at the other end on the pin axle of the rotating shaft, a handle of the hand shank is arranged between a self-locking nut and the L-shaped hanging plate, and the split pins which penetrate through the pin axle are arranged on the self-locking nut. The locking device capable of being opened inside and outside disclosed by the invention has the beneficial effects that the hand shanks are fixed on the pin axle of the rotating shaft through the split pins, and the split pins are drawn out, so that the locking device can be opened outside; the handles of the hand shanks are arranged between the self-locking nut and the L-shaped hanging plate, and the split pins which penetrate through the pin axle are arranged on the self-locking nut, thus the split pins are drawn out, and the hand shanks drive the rotating shaft to rotate to open the locking device inside.