Wearable device comprising sensor

A wearable device comprising:

• a housing including a first side facing a part of a body of a user when the wearable device is worn by the user, and a second side opposite to the first side;
• a hole formed by the second side to pass through the part of the body of the user;
• a sensor module disposed between the first side and the second side, the sensor module including a light emitting unit and a light receiving unit spaced apart from the light emitting unit;
• and
• a processor operatively coupled to the sensor module, a groove disposed between the light emitting unit and the light receiving unit and dent toward the second side from the first side to reduce transmission to the light receiving unit of light emitted from the light emitting unit toward the light receiving unit,
• wherein the processor is configured to:
• emit light toward the part of the body of the user on which the wearable device is worn, using the light emitting unit of the sensor module, and
• obtain biometric information of the user by receiving at least a portion of the light reflected by the part of the body using the light receiving unit of the sensor module.