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 basal-end engaging portion which is disposed on a first end portion of the body portion in a circumferential direction of the wrist and on a side of a surface opposite to a detection surface in the body portion, and with which a basal end portion of the band is engaged; an arbitrary-position engaging portion which is disposed on a second end portion of the body portion in the circumferential direction and on the detection surface, and with which an arbitrary position between the basal end portion engaged with the basal-end engaging portion and a tip end portion of the band is engaged in a folded back state; and engagement members which are configured to detachably engage the tip end portion with the band in a state where the band which is folded back in the arbitrary-position engaging portion and the basal end portion engaged with the basal-end engaging portion overlap with each other, wherein the basal-end 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 arbitrary-position engaging portion is configured by a second member which is erected from the second end portion of the body portion and which has a Π-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 basal-end engaging portion which is disposed on a first end portion of the body portion in a circumferential direction of the wrist and on a side of a surface opposite to a detection surface in the body portion, and with which a basal end portion of the band is engaged; an arbitrary-position engaging portion which is disposed on a second end portion of the body portion in the circumferential direction and on the detection surface, and with which an arbitrary position between the basal end portion engaged with the basal-end engaging portion and a tip end portion of the band is engaged in a folded back state; and engagement members which are configured to detachably engage the tip end portion with the band in a state where the band which is folded back in the arbitrary-position engaging portion and the basal end portion engaged with the basal-end engaging portion overlap with each other, wherein the basal-end 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 arbitrary-position engaging portion is configured by a second member which is erected from the second end portion of the body portion and which has a Π-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.