A biological cell sorter, comprising: a first laser for emitting a first laser beam directed to a point in a tube conducting biological cells in a single file, a first light detector for detecting a cell to be destroyed according to a light emitted from the cell as a result of impinging the first laser beam upon the cell and producing a trigger signal when a cell to be destroyed is detected; a second laser for emitting a second laser beam directed to another point in said guide path downstream of the mentioned point when the trigger signal is supplied thereto; a delay circuit for delaying activation of the second laser by a delay time corresponding to a travel time which the cell requires to travel between the two points; a time measuring circuit for measuring a time interval between two succeeding trigger signals; and a correction circuit such as a look-up table for adjusting the delay time according to said time interval between the two succeeding trigger signals. Thus, even when the response time of the second laser beam is affected by the frequency of second laser beam emission, it is possible to destroy the cells to be destroyed with an extremely high precision. Owing to the high precision achieved by the present invention, the second laser beam can be accurately directed to the intended cells, and the power efficiency of the second laser can be improved.