There is provided a portable electronic apparatus including an apparatus main body that includes electronic components built therein, a fixation belt that is used to attach the apparatus main body to a living body surface, a connector that is provided at an end of the fixation belt in a belt longitudinal direction, and has an engagement protrusion that is detachably stored in an engagement recess formed at the apparatus main body, and a biasing body that is provided in the engagement recess, and biases the engagement protrusion stored in the engagement recess so as to maintain an engagement state between the engagement recess and the engagement protrusion.