A safety device for a power window is achieved, which considers variation in capacitance during raising of a window glass, and considers variation in capacitance due to a use situation so as to reduce a possibility of false operation.
The safety device has a window position counter that allows repetitive pulses to be generated depending on amount of rotation of a raising/lowering motor that raises or lowers a window glass, and counts the pulses to acquire opening information of the window glass; a storage unit that detects capacitance of an electrode provided on the window glass during raising of a window glass, and stores change in the capacitance with being related to window position information given by the window position counter; and a controller that sets a reversal threshold value with the stored change in capacitance, which is stored in the storage unit with being related to the window position information, as a reference, and reverses the raising/lowering motor to lower the window glass irrespective of a state of the operational switch in the case that a value of capacitance detected by a capacitance detector during raising operation of the window glass exceeds the reversal threshold value for each window position information.