A device for measuring profiles of an electron beam and a laser beam is provided with a profile measuring device 30 for measuring cross-section profiles of the beams in the vicinity of a collision position where an electron beam 1 and a laser beam 3 are brought into frontal collision, and a moving device 40 for continuously moving the profile measuring device in a predetermined direction which substantially coincides with the axial directions of the beams. Furthermore, based on the cross-section profiles measured by the profile measuring device, the position of the profile measuring device in the predetermined direction, and the oscillation timings of the beams, temporal changes in three-dimensional profiles of the electron beam and the laser beam are created by a profile creating device 50.