Vehicle seat with automatically height-adjustable head rest, said vehicle seat comprising a seat frame, a rest frame, a guiding assembly and a head rest, wherein - said guiding assembly is formed by two longitudinally with respect to the vehicle extending guides, which are fixable to a vehicle body in the area of mounting each seat; - said seat frame comprises at least a pair of lateral beams, which extend longitudinally with respect to the vehicle and are spaced apart from each other and firmly interconnected with each other by means of transversal spacers, wherein said seat frame is embedded within said guides of the guiding assembly with the possibility of being displaced along said guides and blocked in each desired position; - said rest frame comprises at least a pair of lateral beams, which are spaced apart from each other and firmly interconnected by means of transversal spacers, and it is on its end portion apart from the seat frame furnished with guiding bushes (24', 24"), which are parallel to each other and at least approximately to said lateral beams and are moreover adapted to receive the head rest, wherein said rest frame is pivotally attached to the seat frame such that the rest frame can be pivoted relative to the seat frame and fixed in each desired position; - said head rest comprises a body, which is inserted through said guiding bushes (24', 24") on the rest frame, as well as at least one longitudinal beam which is intended for displacing the head rest along said guiding bushes (24', 24") and relative to the rest frame; - wherein a transmission assembly comprises at least one flexible transmission element (51, 52) suitable for transferring longitudinal displacements of the seat frame relative to each guide towards the area of the longitudinal beam for the purposes of displacing the body of the head rest along said guiding bushes (24', 24") and relative to the rest frame, and wherein said transmission assembly is conceived in such a manner that each forward or rearward displacement of the seat frame relative to said guides of the guiding assembly is transferred into the area in which the head rest is embedded on the rest frame via at least one flexible transmission element (51, 52) and at least one compensation assembly, wherein each displacement of said seat frame relative to the guides is simultaneously followed with a displacement of the head rest relative to the rest frame, the length and/or time dependency of which is different from the length and/or time dependency of said displacement of the seat frame relative to the guide, and moreover the body of the head rest is displaceable along at least one of said guiding bushes (24', 24 ") and relative to the rest frame either in a step-like manner or in a continuous manner, characterized in that the transmission assembly comprises a curved coulisse guide, which is arranged adjacent to said guide of the seat frame and is firmly connected thereon, wherein said coulisse guide is designed in such a manner that, when observed in the longitudinal direction of said guides of the seat frame, the distance between said coulisse guide and said guides of the seat frame is changing in a predefined manner, and wherein a slider is inserted within said coulisse guide and is attached to one of the transversal spacers of the seat frame with the possibility of being displaced along said transversal spacer and at least one of said transmission elements (51, 52) is attached thereto, which is intended to transform each displacement of the seat frame relative to each of said guides into a desired displacement of the head rest relative to the rest frame and which is on the other hand connected with the longitudinal beam for displacing the head rest. - said guiding assembly is formed by two longitudinally with respect to the vehicle extending guides, which are fixable to a vehicle body in the area of mounting each seat; - said seat frame comprises at least a pair of lateral beams, which extend longitudinally with respect to the vehicle and are spaced apart from each other and firmly interconnected with each other by means of transversal spacers, wherein said seat frame is embedded within said guides of the guiding assembly with the possibility of being displaced along said guides and blocked in each desired position; - said rest frame comprises at least a pair of lateral beams, which are spaced apart from each other and firmly interconnected by means of transversal spacers, and it is on its end portion apart from the seat frame furnished with guiding bushes (24', 24"), which are parallel to each other and at least approximately to said lateral beams and are moreover adapted to receive the head rest, wherein said rest frame is pivotally attached to the seat frame such that the rest frame can be pivoted relative to the seat frame and fixed in each desired position; - said head rest comprises a body, which is inserted through said guiding bushes (24', 24") on the rest frame, as well as at least one longitudinal beam which is intended for displacing the head rest along said guiding bushes (24', 24") and relative to the rest frame; - wherein a transmission assembly comprises at least one flexible transmission element (51, 52) suitable for transferring longitudinal displacements of the seat frame relative to each guide towards the area of the longitudinal beam for the purposes of displacing the body of the head rest along said guiding bushes (24', 24") and relative to the rest frame,