An interpolation circuit includes: a generation circuit that generates interpolation data from a plurality of pieces of input data, using an interpolation coefficient, among input data inputted in time series including a data point and a transition point; a detection circuit that detects that the input data lacks at the data point; and a coefficient circuit that changes the interpolation coefficient for each given data interval, and skips a position for changing the interpolation coefficient to the transition point when the detection circuit detects the lack of the input data.