A device for measuring biological information by being worn on a person includes a sensor unit subjected to measure biological information, a device main unit provided with a concavity and subjected to accommodate the sensor unit, and a holding unit supported on one side by the sensor unit and on the other side by the device main unit wherein the holding unit is elastic and has a space on one side of the concavity to hold the sensor unit so that at least part of the sensor unit extends outside from the device main unit, and wherein the sensor unit is displaced relative to the device main unit by elastic deformation in accordance with an external force applied to the sensor unit.