Polyorganosiloxane, polycarbonate - polyorganosiloxane copolymer and a production method thereof

Provided is a polyorganosiloxane in which the value that results from integrating the dw/dlog(M) value in the range of 2.5 ≤ log(M) ≤ 3.1 is 0-10% with respect to the value that results from integrating the dw/dlog(M) value in the entire range of log(M) in a differential molecular weight distribution curve that is obtained from measurement by gel permeation chromatography in which polystyrene is used as a basis for conversion, the horizontal axis is the logarithmic value log(M) of the molecular weight (M), and the vertical axis is the dw/dlog(M) that is the result of differentiating the concentration factor (w) by the logarithmic value log(M) of the molecular weight.