Timepiece and timepiece case

A timepiece comprising:

• a casing that has an open first end;
• a light transmission part disposed at the first end;
• a function part disposed inside the casing;
• and
• a glue that adheres the light transmission part to the casing,
• wherein the casing includes
• a projection that projects from an inner circumferential surface of the casing toward an inside of the casing and that extends along a circumferential direction and
• a protrusion that protrudes from the inner circumferential surface toward the inside of the casing and that determines a position of the light transmission part with respect to the inner circumferential surface,
• wherein a lateral surface of the light transmission part is adhered to the inner circumferential surface by the glue, and a peripheral part of a bottom surface of the light transmission part is adhered to a top surface of the projection by the glue,
• wherein an outer circumferential surface of the function part extends along an inner surface of the projection,
• wherein a space is present in a facing region where the projection faces the function part along the light transmission part,
• wherein in the facing region, the space is wider in a specific section including a position of the protrusion than in a section different from the specific section.