The invention provides an automobile seat with an adjustable headrest mechanism and a vehicle, and relates to the technical field of vehicles. The automobile seat is provided with an adjustable headrest mechanism, and the headrest mechanism comprises a headrest, a connecting rod, a connecting piece, an elastic steel wire and a lower fixing piece which are sequentially connected from top to bottom.The connecting piece can move along a guide rail fixed on the framework, and the lower fixing piece can be arranged on the framework in an up-down adjusting mode. The headrest mechanism also comprises a pull-up spring arranged between the framework and the connecting piece and an adjusting device. The adjusting device is arranged on the framework and used for locking/unlocking the lower fixing piece. When the adjusting device and the lower fixing piece are in an unlocking state, the connecting piece can move along the guide rail under the pulling force of the pull-up spring so as to adjust the position of the headrest. Through the simple mechanical structure, the headrest can be adjusted to the most comfortable position of the headrest without difficulty in the running process of the vehicle, so that the man-machine requirement is met, and the comfort is strong.