A syringe pump includes a syringe diameter detection means (103) for detecting a syringe volume, an accumulated quantity calculation means for calculating the accumulated quantity of infusion at the start of infusion, and an occlusion reduction means (116) for reducing the internal syringe pressure by driving a slider assembly (6) in a direction opposite to the infusing direction when an occluded state is greater than or equal to a specified value. When the syringe volume at the start of infusion is less than or equal to the accumulated quantity of infusion, the internal pressure reduction means is caused to stop reducing the internal syringe pressure.
