Abstract: A signal measurement apparatus is provided which does not require a special pattern to measure and evaluate reproduced data of a digital signal. RF data, which is binary-coded data obtained by reproducing digital recorded signal, and latch data obtained by latching the RF data in response to a reproduction clock signal reproduced by using the RF data are supplied through a signal input terminal thereof and respectively supplied to a first-pattern-length detection section and a second-pattern-length detection section so that the pattern lengths of predetermined patterns are measured. Then, a 2D display section plots the first pattern lengths on the X axis and the second pattern lengths on the Y axis to 2D-display the first and second pattern lengths.