Detection device and timepiece

A detection device comprising:

• a light emitter that emits light toward a first direction;
• a light receiver;
• a back cover with a first opening corresponding to the light emitter and a second opening corresponding to the light receiver;
• a window which is provided on a first direction side of the back cover and in which a metal base and a light transmitter are integrated with each other, the metal base being formed with a third opening corresponding to the light emitter and a fourth opening corresponding to the light receiver, and the light transmitter closing each of the third opening and the fourth opening;
• and
• a light shield that is provided between the window and the back cover, wherein
• the light shield is provided to correspond to at least part of a region corresponding to an outer circumference of the light emitter and an entire circumference of a region corresponding to an outer circumference of the light receiver, and
• the window is bonded to the back cover by an adhesive over an entire outer circumference.