A pressure pulse wave sensor comprising: a sensor chip which includes a semiconductor substrate including: a pressure-sensitive element row configured by a plurality of pressure-sensitive elements that are arranged in one direction; and a chip-side terminal portion (10B, 10C, 10E) that is placed in an end portion in the one direction of a pressure-sensitive surface on which the pressure-sensitive element row is formed, and that is electrically connected to the pressure-sensitive element row, the semiconductor substrate further including a concave portion including a thin portion in which a thickness in a direction perpendicular to the pressure-sensitive surface is smaller than a thickness of another portion, the sensor chip to be used while the pressure-sensitive surface is pressed against a body surface of a living body in a state where the one direction intersects a traveling direction of an artery of the living body; and a substrate which includes a concave portion, the semiconductor substrate of the sensor chip being fixed to a bottom surface of the concave portion, wherein a substrate-side terminal portion (11B, 11C, 11E) for being electrically connected to the chip-side terminal portion (10B, 10C, 10E) is disposed on a surface of a side wall of the concave portion of the substrate, the surface being at a predetermined height with respect to the bottom surface of the concave portion, and the pressure pulse wave sensor further comprises: an electroconductive member (W1, W2) which connects the chip-side terminal portion (10B, 10C, 10E) and the substrate-side terminal portion (11B, 11C, 11E) to each other; and a protective member which covers the electroconductive member (W1, W2), characterized in that a gap between an end surface in the one direction of the sensor chip and the substrate is filled with a material which is less changed in volume than the protective member depending on a temperature and a humidity. a sensor chip which includes a semiconductor substrate including: a pressure-sensitive element row configured by a plurality of pressure-sensitive elements that are arranged in one direction; and a chip-side terminal portion (10B, 10C, 10E) that is placed in an end portion in the one direction of a pressure-sensitive surface on which the pressure-sensitive element row is formed, and that is electrically connected to the pressure-sensitive element row, the semiconductor substrate further including a concave portion including a thin portion in which a thickness in a direction perpendicular to the pressure-sensitive surface is smaller than a thickness of another portion, the sensor chip to be used while the pressure-sensitive surface is pressed against a body surface of a living body in a state where the one direction intersects a traveling direction of an artery of the living body; and a substrate which includes a concave portion, the semiconductor substrate of the sensor chip being fixed to a bottom surface of the concave portion, wherein a substrate-side terminal portion (11B, 11C, 11E) for being electrically connected to the chip-side terminal portion (10B, 10C, 10E) is disposed on a surface of a side wall of the concave portion of the substrate, the surface being at a predetermined height with respect to the bottom surface of the concave portion, and the pressure pulse wave sensor further comprises: an electroconductive member (W1, W2) which connects the chip-side terminal portion (10B, 10C, 10E) and the substrate-side terminal portion (11B, 11C, 11E) to each other; and a protective member which covers the electroconductive member (W1, W2), an electroconductive member (W1, W2) which connects the chip-side terminal portion (10B, 10C, 10E) and the substrate-side terminal portion (11B, 11C, 11E) to each other; and a protective member which covers the electroconductive member (W1, W2), characterized in that a gap between an end surface in the one direction of the sensor chip and the substrate is filled with a material which is less changed in volume than the protective member depending on a temperature and a humidity.