Pulse wave sensor

A pressure pulse wave sensor for detecting a pressure pulse wave produced from an arterial vessel of a living subject in synchronism with a heartbeat of the subject comprising:

• a press surface adapted to be pressed on a body surface of the subject;
• a protruding portion protruding from said press surface and having a top surface, said top surface of said protruding portion being covered with a resilient protective layer, which is formed of a first material;
• at least one pressure sensing element provided in said top surface of said protruding portion for detecting said pressure pulse wave produced from said arterial vessel;
• and
• a hard member which surrounds said protruding portion such that a top end of said hard member is substantially flush with said resilient protective layer covering said top surface of said protruding portion, said hard member being formed of a second material which is different from said first material and having a hardness higher than that of said resilient protective layer.