A film mode detecting apparatus and method for detecting a film mode by using a periodicity of motion vectors having high autocorrelativity. A motion vector calculating unit adds a size of motion vectors with respect to each field, thereby outputting a first computing value. A peak value eliminating unit detects a peak value from the first computing value, and if the peak value is detected, eliminates the peak value from the first computing value and outputs a resultant value. A mode detecting unit compares an autocorrelation coefficient with a predetermined threshold, thereby outputting a film mode detection signal. The autocorrelation coefficient is obtained from an input signal inputted from the peak value eliminating unit and a delayed signal delayed from the input signal. A mode determining unit determines a film mode when the film mode detection signal is input as often as, or more often than, a first reference value. A scene change detecting unit is further provided for detecting a scene change when the peak value is detected by the maximum value detecting unit, by comparing the detected peak value with a previously detected peak value, and outputting a scene change detection signal to the mode determining unit. In this case, the mode determining unit determines whether it is a film mode or not in accordance with the detection result from the scene change detecting unit based on a second reference value which is greater than the first reference value.