To provide a novel crosslinking system of fluorine-containing elastomer giving a crosslinked product particularly having improved mechanical strength and compression set at high temperature. According to the method, a multi-axial load locus representing the tangible structure is generated. Further, in second image-pickup, acquires second image data for the AF area within the image frame according to a second light flux from the object passing through the aperture of the diaphragm when the diaphragm is shifted in one vertical direction with respect to the optical axis. s or higher to a cooling termination temperature in the range of 525 to 625\xb0 C. A crosslinked polymer having a tertiary amine andor a quaternary ammonium salt structure, said crosslinked polymer has a tertiary amine structure at either end of at least one crosslink structure.