A method for controlling an imaging device that can easily switch the imaging wavelength band, and an imaging device are provided. A method is for controlling an imaging device (110) that allows switching of an operation mode between a first mode to perform imaging in a first imaging wavelength band and a second mode to perform imaging in a second imaging wavelength band different from the first imaging wavelength band. The method includes: determining whether ambient light includes near-infrared light based on information obtained in the first mode and information obtained in the second modein a case that the operation mode is the first mode; continuing the first mode if the ambient light includes near-infrared light; switching the operation mode into the second mode if the ambient lightdoes not include the near-infrared light; determining whether the ambient light includes the near-infrared light based on the information obtained in the first mode and the information obtained in the second mode in a case that the operation mode is the second mode; switching the operation mode into the first mode if the ambient light includes the near-infrared light; and continuing the second mode if the ambient light does not include the near-infrared light.