A pneumatic wrench includes a handlebar having a main body, two extension walls defining an engagement notch therebetween, and a first air channel extending inside the main body and the two extension walls, and a tool head having a head portion, a neck portion extending from the head portion into the engagement notch, and a second air channel extending inside the head and neck portions. A pivot shaft is inserted through the handlebar and the tool head such that the tool head is swingable relative to the handlebar. The pivot shaft has a shaft body with a shaft hole, and two first and one second through holes in air communication with the shaft hole. The first air channel is communicated with the second air channel via the first and second through holes and the shaft hole. As such, the pneumatic wrench is angle-adjustable to fulfill user's need.