Molecule detection sensor, detection sensor, and gas transferring pump

A detection sensor comprising:

• a detection unit that detects a substance having a mass contained in gas;
• and
• a pump that pumps the gas into the detection unit,
• wherein the pump comprises:
• a pump main body in which a flow passage is formed to externally pump the gas into the detection unit;
• a volume change generating unit that changes the volume of the gas in the flow passage;
• and
• a counter-flow reducing unit that hinders the gas from moving away from the detection unit in the flow passage when the volume change generating unit changes the volume of the gas.

A gas transferring pump comprising:

• a chamber formed in the pump;
• a first channel formed to allow the chamber to communicate with an exterior of the pump;
• a second channel formed to allow the chamber to communicate with the exterior of the pump at a position different from that for the first channel;
• a first reduced diameter portion formed between the chamber and the first channel and having an inner diameter gradually decreasing from the first channel toward the chamber;
• a second reduced diameter portion formed between the chamber and the second channel and having an inner diameter gradually decreasing from the chamber toward the second channel;
• and
• temperature changing means for changing a temperature in the chamber.