A pulse wave detector which is used while being attached to a wrist of a measurement subject, the pulse wave detector comprising: a body portion which includes a detecting section disposed in a position which is opposed to a radial artery of the measurement subject and configured to detect a pulse wave from the radial artery; a band which is configured to be wound around the wrist in a state where the band is engaged with the body portion; a first engaging portion which is disposed on a first end portion that is one of end portions of the body portion on a side of an ulna of the wrist in a circumferential direction of the wrist and on a side of an opposite surface of the body portion which is opposite to a detection surface of the body portion which is opposed to the wrist, and with which a basal end portion in a longitudinal direction of the band is engaged; a second engaging portion which is disposed on a second end portion that is one of the end portions of the body portion on a side of a radius of the wrist in the circumferential direction and on the detection surface, and with which an arbitrary position in the longitudinal direction of the band engaged with the first engaging portion is engaged in a state where the band is folded back in a direction to be separated from the body portion; and engagement members which are configured to engage a tip end portion in the longitudinal direction of the band with the basal end portion in a state where the basal end portion engaged with the first engaging portion and the tip end portion of the band engaged with the second engaging portion overlap with each other, wherein the tip end portion is engaged with the basal end portion through the engagement member in a state where a tip end of the tip end portion is directed from a side of the detection surface to a side of the opposite surface, wherein the first engaging portion is configured by a first member which is erected from the first end portion of the body portion and which has a Π-shape, and a first hole portion is formed between the first member and the first end portion of the body portion, wherein the second engaging portion is configured by a second member which is erected from the second end portion of the body portion and which has a II-shape, and a second hole portion is formed between the second member and the second end portion of the body portion, and wherein the engagement members are formed on surfaces of the basal end portion and the tip end portion of the band. a body portion which includes a detecting section disposed in a position which is opposed to a radial artery of the measurement subject and configured to detect a pulse wave from the radial artery; a band which is configured to be wound around the wrist in a state where the band is engaged with the body portion; a first engaging portion which is disposed on a first end portion that is one of end portions of the body portion on a side of an ulna of the wrist in a circumferential direction of the wrist and on a side of an opposite surface of the body portion which is opposite to a detection surface of the body portion which is opposed to the wrist, and with which a basal end portion in a longitudinal direction of the band is engaged; a second engaging portion which is disposed on a second end portion that is one of the end portions of the body portion on a side of a radius of the wrist in the circumferential direction and on the detection surface, and with which an arbitrary position in the longitudinal direction of the band engaged with the first engaging portion is engaged in a state where the band is folded back in a direction to be separated from the body portion; and engagement members which are configured to engage a tip end portion in the longitudinal direction of the band with the basal end portion in a state where the basal end portion engaged with the first engaging portion and the tip end portion of the band engaged with the second engaging portion overlap with each other, wherein the tip end portion is engaged with the basal end portion through the engagement member in a state where a tip end of the tip end portion is directed from a side of the detection surface to a side of the opposite surface, wherein the first engaging portion is configured by a first member which is erected from the first end portion of the body portion and which has a Π-shape, and a first hole portion is formed between the first member and the first end portion of the body portion, wherein the second engaging portion is configured by a second member which is erected from the second end portion of the body portion and which has a II-shape, and a second hole portion is formed between the second member and the second end portion of the body portion, and wherein the engagement members are formed on surfaces of the basal end portion and the tip end portion of the band.