An apparatus for locking a shift lever of an automatic transmission in a vehicle may include a shift lock cam including a position converting member and being connected with a brake pedal wherein the shift lock cam is pivotally coupled to a shift lever housing and elastically supported by a first elastic member, and a shift lock release lever that is pivotally coupled to the shift lever housing and elastically supported by a second elastic member, wherein one end of the shift lock release lever is selectively coupled to a shift lever body and the other end of the shift lock release lever is eccentrically coupled to the position converting member of the shift lock cam.