PURPOSE: To capture a particle by surely converging a laser beam without scattering the laser beam even when the optical axis is more or less inclined or shifted without using a cone prism being very difficult to presicely manufacture.

CONSTITUTION: In a laser trapping device for capture a particle 2 by converging a laser beam on the focus by means of a condensing optical system 5 and projecting it on the particle 2 in vacuum or in a medium, a prism 3 for dividing the laser beam into plural parallel luminous fluxes is arranged before the condensing optical system 5, the both ends of the prism 3 on the entrance side and the exit side of the laser beam is formed by the same number of more than two planes 6A, 6B, 7A, 7B, and paired planes 6A and 7A, 6B and 7B on the entrance side and the exit side are formed parallel to each other.