A pulse wave sensor unit includes a pressure sensor, and an adhesive tape to attach the pressure sensor to a measurement portion to be measured. The pressure sensor includes a diaphragm part, and an annular support part which supports the diaphragm part and has an aperture for allowing the diaphragm part to face the measurement portion, and a closed space is able to be formed between the diaphragm part and the measurement portion by attaching the pressure sensor to the measurement portion using the adhesive tape.