Infrared spectrometer

An infrared spectrometer comprising

• an openable sealed housing that houses optical components;
• an infrared light source that irradiates an infrared light into the sealed housing;
• a dehumidifier that dehumidifies an inside of the sealed housing;
• a thermo-hygro sensor that detects a humidity inside the sealed housing;
• and
• a controller that controls power supply to the infrared light source,
• takes out the infrared light as a measurement light via the optical components inside the sealed housing, irradiates the measurement light to a sample disposed outside the sealed housing, and acquires a spectrum based on a detected value of a light from the sample,
• wherein the controller:
• starts the infrared light source while limiting power supply to the infrared light source;
• determines presence/absence of a risk of condensation inside the sealed housing based on a detected value of humidity detected while power is supplied to the infrared light source;
• and,
• when the risk of condensation is determined to be present, balances a rate of increase of the detected value of humidity detected while power is supplied to the infrared light source and a rate of decrease of humidity dehumidified by the dehumidifier, and at the same time, gradually increases power supply to the infrared light source.