A printing element substrate, including a printing element, a switching element which drives the printing element based on an input control signal, a first current source which generates a predetermined current, a second current source which generates a current based on an input voltage, and a current generation circuit which generates the control signal by amplifying a current obtained by adding a current generated by the second current source to a current generated by the first current source, and then generates the control signal by amplifying a current generated by the first current source.