A sensor controller is for a particulate matter detection sensor that includes a pair of opposed electrodes spaced from each other and disposed on an attachment portion. The sensor controller includes a calculation portion configured to calculate an amount of particulate matter attached to the particulate matter detection sensor based on a detection value from the particulate matter detection sensor, and a determination portion configured to determine whether water exists in the exhaust passage based on the detection value. Thus, it is possible to accurately determine whether water exists in the exhaust passage.