Abstract: Provided is a device for adjusting a seat of a vehicle. The device integrates a fold-and-dive function in addition to a walk-in function of a seat and also enables a forward or backward sliding movement function of the seat to be linked with other functions, so that the walk-in operation that tilts second-row seats or third-row seats to a forward direction for securing an aisle for a passenger to get in or out of the vehicle may be easily performed. Further, the walk-in operation state may be robustly maintained since the seat is robustly fixed after the walk-in operation is performed, and the device contributing to a standardization in which various functions in addition to the walk-in function are integrated with each other and contributing to functional expandability may be provided.