Abstract: The present disclosure relates to an apparatus for measuring bio-information, the apparatus including a heart rate sensor unit configured to measure heart rates by receiving a light that has entered and come out from skin, an acceleration sensor unit configured to output a step count by measuring the step count of a wearer, a display unit configured to display the measured heart rates and step count, and a wrist-wearable connection unit configured to electrically connect the heart rate sensor, the acceleration sensor unit and the display unit, whereby heart rate can be accurately measured using a line light source instead of point light source, even if the apparatus is not fully attached to a wrist. The apparatus includes a heart rate sensor unit configured to improve a light receiving efficiency using four light receiving units.