To provide an air conditioner for board capable of reducing generation of noise.

This air conditioner for board comprises a casing 1 divided to a first chamber 9 and a second chamber 10 by a partition wall 2. The second chamber 10 has an outside air intake port 21 and a warm air discharge port 22 in the first surface 1c of the casing 1. A condenser 6 is arranged in a position opposed to the intake port 21 or discharge port 22, and a second fan 12 is provided between the intake port 21 and the discharge port 22 so that a blade is rotated along a plane substantially orthogonal to the first surface 1c. The second fan 12 is opposed to two side surfaces of the casing substantially orthogonal to the first surface 1c.