Sensor manufacturing method and sensor

A sensor comprising:

• a generator that generates a predetermined detection target;
• a detector that detects the detection target generated by the generator;
• a substrate on which the generator and the detector are installed;
• a motion body that performs motion in an area in between the generator and the detector;
• and
• a housing that houses the generator, the detector, and the motion body, wherein
• the substrate
• has a first portion, on which the generator is installed, and a second portion, on which the detector is installed, formed in an integrated manner,
• has a curved shape or a bent shape in such a way that the generator and the detector are positioned opposite to each other, and
• is disposed at such a position that the motion body is present in the area in between the generator and the detector, and
• the housing includes a first member on which the substrate is mounted and includes a second member at which the motion body is installed.