An electrical steering lock device and a related method are disclosed wherein a plate cam 17 has a contoured profile determined such that a lock shaft 15 moves inside a lock groove 13 at a travel speed (first speed) lower than a travel speed (second speed) at which the lock shaft 15 moves outside the lock groove 13, enabling the lock shaft 15 to disengage from the lock groove 13 with increased torque. This results in a capability of reliably disengaging the lock shaft 15 from the lock groove 13.