An ink jet recording head, comprising: first and second recording element substrates (H1100, H1101), wherein each of the recording element substrates (H1100, H1101) comprises a recording element for producing thermal energy to cause generation of a bubble in recording liquid to cause ejection of recording liquid; an ejection outlet, facing the recording element, to eject recording liquid; and a recording liquid supply port, coupled by a flow path to the ejection outlet, to supply the recording liquid to the recording element; and driving means for driving the recording elements to cause ejection of recording liquid; wherein the shortest distance between the recording element and an outer surface of the ejection outlet is greater in the first recording element substrate than in the second recording element substrate, characterized in that the first recording element substrate being a different substrate with respect to the second recording element substrate, the distance between the recording element and the outer surface of the ejection outlet in the first recording element substrate is such that, in operation of the driving means, a bubble generated in the recording liquid in the first recording element substrate by thermal energy produced by the recording element of the first recording element substrate collapses without liquid communication with the atmosphere outside the liquid path of the first recording element substrate, and the distance between the recording element and the outer surface of the ejection outlet in the second recording element substrate is such that, in operation of the driving means, a bubble generated in the recording liquid in the second recording element substrate by the thermal energy produced by the recording element of the second recording element substrate is brought into liquid communication with the atmosphere outside of the second recording element substrate. first and second recording element substrates (H1100, H1101), wherein each of the recording element substrates (H1100, H1101) comprises a recording element for producing thermal energy to cause generation of a bubble in recording liquid to cause ejection of recording liquid; an ejection outlet, facing the recording element, to eject recording liquid; and a recording liquid supply port, coupled by a flow path to the ejection outlet, to supply the recording liquid to the recording element; and driving means for driving the recording elements to cause ejection of recording liquid; wherein the shortest distance between the recording element and an outer surface of the ejection outlet is greater in the first recording element substrate than in the second recording element substrate, characterized in that the first recording element substrate being a different substrate with respect to the second recording element substrate, the distance between the recording element and the outer surface of the ejection outlet in the first recording element substrate is such that, in operation of the driving means, a bubble generated in the recording liquid in the first recording element substrate by thermal energy produced by the recording element of the first recording element substrate collapses without liquid communication with the atmosphere outside the liquid path of the first recording element substrate, and the distance between the recording element and the outer surface of the ejection outlet in the second recording element substrate is such that, in operation of the driving means, a bubble generated in the recording liquid in the second recording element substrate by the thermal energy produced by the recording element of the second recording element substrate is brought into liquid communication with the atmosphere outside of the second recording element substrate.