Disclosed herein is a microparticles measuring apparatus including: an optical detecting section configured to direct a laser beam toward microparticles passing through a flow channel, detect light emanating from the microparticles, and convert the detected light into electrical signals; and a controlling unit configured to calculate the speed of the microparticles passing through the flow channel according to the electrical signals and suspend the supply of solution containing the microparticles when the calculated speed exceeds a prescribed limit.