The invention discloses an image detection device has an image detector equipped with a detection section having a charge generation section that receives irradiation of electromagnetic waves and generates charges, a storage capacitor in which two electrodes are disposed so as to oppose one another and which accumulates charges generated at the charge generation section, and a TFT switching element for reading out charges accumulated in the storage capacitor. At a time before a point in time of reading out of charges from the storage capacitor via the switching element of the image detector, a reference potential of the storage capacitor is varied by a variable Cs power source, and leak current sufficiently flows before reading out of a charge signal from the image detector. Leak current is thereby reduced sufficiently at a time of reading out the charge signal.