PROBLEM TO BE SOLVED: To perform initial acquisition and high accuracy acquisition, to reduce loss of an optical beam to be received at a reception part to the minimum, and to perform acquisition tracking even when a light receiving amount is a minute amount by a simple configuration.SOLUTION: An acquisition tracking device includes: first optical path deflection means 1 for deflecting an optical beam; condensation means 3 for condensing the optical beam; second optical path deflection means 5 for deflecting the optical beam; a pin hole 4 which is provided to the second optical path deflection means 5, near a condensation spot and with size equal to or more than condensation spot size when the optical beam matches to a reference optical axis 30; a reception part 10 which receives the optical beam passed through the second optical path deflection means 5; first optical detection means 6 for detecting angle deviation between the optical beam and the reference optical axis based on the optical beam deflected by the second optical path deflection means 5; optical branching means 2 for branching the optical beam; second optical detection means 7 for detecting the angle deviation between the optical beam and the reference optical axis 30 with high accuracy based on the branched optical beam; and deflection direction correction means 8 for correcting the deflection direction of the first optical deflection means 1 based on the angle deviation.
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