A pneumatic tire comprising: a tread portion comprising a first tread pattern formed between a tire equator (Co) and one of tread edges and a second tread pattern formed between the tire equator (Co) and the other one of the tread edges, the first tread pattern and the second pattern being formed as substantially line symmetrical shape with respect to the tire equator (Co) and being shifted with respect to one another in a tire circumferential direction; each of the first and second tread patterns (P1, P2) being provided with lateral inclined grooves each extending axially inwardly from the tread edge to an axially inner end located adjacent to the tire equator (Co) without reaching the tire equator (Co), and connecting inclined grooves each having an inclination opposite to the lateral inclined grooves and connecting a pair of circumferentially adjacent lateral inclined grooves, wherein the pair of circumferentially adjacent lateral inclined grooves is connected by at least one connecting inclined groove; and central connecting grooves each extending across the tire equator (Co) to connect one of the lateral inclined grooves arranged on the first tread pattern with one of the lateral inclined grooves arranged on the second tread pattern, wherein the central connecting grooves each having a depth smaller than depths of the lateral inclined grooves, and wherein the central connecting grooves each comprise a first end and a second end such that the first end is located nearer to the tire equator (Co) than the second end, characterized in that the depth decreases gradually from the first end to the second end. a tread portion comprising a first tread pattern formed between a tire equator (Co) and one of tread edges and a second tread pattern formed between the tire equator (Co) and the other one of the tread edges, the first tread pattern and the second pattern being formed as substantially line symmetrical shape with respect to the tire equator (Co) and being shifted with respect to one another in a tire circumferential direction; each of the first and second tread patterns (P1, P2) being provided with lateral inclined grooves each extending axially inwardly from the tread edge to an axially inner end located adjacent to the tire equator (Co) without reaching the tire equator (Co), and connecting inclined grooves each having an inclination opposite to the lateral inclined grooves and connecting a pair of circumferentially adjacent lateral inclined grooves, wherein the pair of circumferentially adjacent lateral inclined grooves is connected by at least one connecting inclined groove; and lateral inclined grooves each extending axially inwardly from the tread edge to an axially inner end located adjacent to the tire equator (Co) without reaching the tire equator (Co), and connecting inclined grooves each having an inclination opposite to the lateral inclined grooves and connecting a pair of circumferentially adjacent lateral inclined grooves, wherein the pair of circumferentially adjacent lateral inclined grooves is connected by at least one connecting inclined groove; and central connecting grooves each extending across the tire equator (Co) to connect one of the lateral inclined grooves arranged on the first tread pattern with one of the lateral inclined grooves arranged on the second tread pattern, wherein the central connecting grooves each having a depth smaller than depths of the lateral inclined grooves, and wherein the central connecting grooves each comprise a first end and a second end such that the first end is located nearer to the tire equator (Co) than the second end, characterized in that the depth decreases gradually from the first end to the second end.