A pressure sensor and a blood pressure measurement device with the pressure sensor are disclosed. The pressure sensor includes a case and a pressure sensing element. Two opposite sides of the case have a concave portion and a convex portion, respectively. A recessed space is formed in the concave portion. The pressure sensing element is disposed on the case. When the convex portion pushes the pressure sensing element, the pressure sensing element is deformed and protruded toward the recessed space. The pressure sensor has a higher detection sensibility.
