Detection device and measurement apparatus

A detection device comprising:

• a holding block configured to hold a transparent tubular body having a curved surface shape;
• an accommodating hole that is formed in the holding block and in which the tubular body is inserted and accommodated;
• an optical sensor comprising a light projecting unit configured to emit detection light for detecting whether or not the tubular body is accommodated in the accommodating hole and a light receiving unit which receives the detection light;
• and
• an optical path of the detection light comprising a tunnel structure covered with a wall surface, the optical path linearly extending inside the holding block in a direction intersecting with the accommodating hole and being formed at a position away from a radial center of the accommodating hole, wherein a wall surface of the accommodating hole and a wall surface of the optical path have are configured to have a light reflectivity of 30% or less due to being subjected to a matte black alumite treatment.