Abstract: An improved pressure balance device for use in a faucet is made up of a pair of symmetric semi-cylindrical units and a tubular water inlet cap. Each semi-cylindrical unit has a semi-circular cross section and on each edge of the vertical face thereof is disposed a locking protrusion and a retaining recess at the middle position thereof respectively. Under the locking protrusion and the retaining recess is disposed a radially extended lug respectively. At the central position of the arc peripheral surface of each semi-cylindrical unit is placed a wedge-shaped locking latch. The tubular water inlet cap is provided with two symmetric inverted U-shaped engagement recesses at the bottom rim thereof and right between the two engagement recesses, in either direction, is disposed a retaining hole whereby the water inlet cap can be snapped into engagement with the two assembled semi-cylindrical units and be locked integrally together with ease and speed.