A printer includes a spectroscope that has a variable wavelength interference filter which incidents light from a measurement region, and a light receiving section which receives light from the variable wavelength interference filter and which outputs a detection signal according to an amount of received light, a carriage moving unit which relatively moves the spectroscope along one direction with respect to a measurement target of spectrometry and moves the measurement region with respect to the measurement target, and a timing detection circuit which has a differential circuit that differentiates the detection signal and outputs a differentiation signal, wherein in a case where the measurement target is a color patch, spectrometry in which the amount of received light is detected starts based on the differential signal.