An object is to provide an optical pulse test method and an optical pulse test device with which it is possible to measure transmission losses of a basic mode and a first higher-order mode at a connection point at which two-mode optical fibers are connected in series, without switching the mode of input test light.
An optical pulse test device according to the present invention inputs a test optical pulse in a basic mode (or a first higher-order mode) from one end of an optical fiber under test, the test optical pulse having such a wavelength that the test optical pulse can propagate in the basic mode and the first higher-order mode, measures intensity distributions of a basic mode component and a first higher-order mode component of return light of the test optical pulse relative to the distance from the one end, finds, from the intensity distributions, losses of the basic mode component and the first higher-order mode component of the return light at a desired connection point of the optical fiber under test, and calculates transmission losses of the basic mode and the first higher-order mode at the connection point based on expressions (8) (or expressions (9)).