Disclosed is a particulate matter measurement device that continuously measures changes in a mass of particulate matters contained in an exhaust gas under dynamic operating conditions. The device dilutes and separates the flow of exhaust gas while an engine is operating. The particulate matters contained in one of the exhaust gas streams are collected by a collection filter to measure the mass and the remainder is measured by a mass-related value measurement. Then, time series change data for the mass of the particulate matter are found based on correlations of the individual measured data. With this arrangement, the flow volume of the dilute exhaust gas that passes through the collection filter and the flow volume of the dilute exhaust gas that is introduced into the mass-related value measurement device are ensured by adjusting the flow volume of the diluting gas that dilutes the exhaust gas.