Printing element substrate and liquid ejection head

A liquid ejection head, comprising:

• a printing element substrate including a substrate in which a plurality of energy generation elements configured to generate energy to eject a liquid are formed, a flow channel formation unit in which a flow channel is formed, and an ejection port formation unit in which a plurality of ejection ports to eject the liquid are formed, wherein
• the substrate, the flow channel formation unit, and the ejection port formation unit are connected to each other in this order,
• in the substrate, a plurality of supply ports including a first supply port and a second supply port adjacent to each other in a first direction and configured to supply the ejection ports with the liquid are formed,
• in the flow channel formation unit, a first support unit and a second support unit configured to support the ejection port formation unit are formed between the first supply port and the second supply port, and
• in the first direction, a distance from the first support unit to a midpoint between the first support unit and the second support unit is longer than a distance from the first support unit to the first supply port, and
• a distance from the second support unit to the midpoint between the first support unit and the second support unit is longer than a distance from the second support unit to the second supply port.