A printed circuit board includes a first substrate, two first circuits formed on a surface of the first substrate, and a thick copper circuit. The thickness of each first circuit is smaller than the thickness of the first substrate, and the first substrate and one of the first circuits cooperatively define a circuit trench. The thick copper circuit is arranged in the circuit trench and is integrally connected to the first circuit, which is corresponding to the groove. The thick copper circuit and the connected first circuit are defined as a thick circuit, and another first circuit is defined as a thin circuit. The length of the thick copper circuit connected to the corresponding first circuit is identical to or greater than 10% of the length of the thick circuit. Additionally, the instant disclosure also provides a method for manufacturing a printed circuit board.