Abstract: The present invention relates to a pneumatic tire of which the stiffness of tread blocks is improved in a circumferential direction. According to embodiments of the present invention, second grooves are formed to have a depth larger than the depth of a first groove so that the volume of the first blocks is similar to the volume of the second blocks and the stiffness of the first blocks is similar to the stiffness of the second blocks. Further, a first angle is made to be larger than a second angle so that the stiffness of the first blocks is similar to the stiffness of the second blocks. Accordingly, there is an effect of improving the braking performance or grip performance of a tire by making the stiffness of the tire uniform in the circumferential direction of the tire.