A pneumatic tire formed with a plurality of rib-shaped land portions separated by circumferential grooves extending in a tread circumferential direction, wherein: elongate projection portions project toward each other from the rib-shaped land portions adjacent to each other with one of the circumferential grooves therebetween, the elongate projection portions being formed in an annular shape extending in the tread circumferential direction; the elongate projection portions confronting each other are disposed with a spacing (d) therebetween such that mutually confronting tip surfaces of the confronting elongate projection portions are adapted to be in contact with each other through elastic deformation of the rib-shaped land portions at a time of grounding of the tire; each of the circumferential grooves has formed therein an inside groove space on a radially inner side of the confronting elongate projection portions , and an outside groove space on a radially outer side of the confronting elongate projection portions ; the confronting elongate projection portions have the mutually confronting tip surfaces thereof formed with a plurality of communication recesses providing communication between the outside groove space and the inside groove space , the communication recesses being formed at intervals in the tread circumferential direction; and each of the communication recesses is formed rectilinearly while being oriented in a direction inclined relative to a radial direction in a tire rotational plane, in such a manner that each communication recess has an inside opening communicating with the inside groove space and an outside opening communicating with the outside groove space , the outside opening being located at a position displaced relative to the inside opening in a tire rotational direction at a time of forward travel of a vehicle so that the radially outer side of each communication recess is advanced from the radially inner side of it in the tire rotational direction. elongate projection portions project toward each other from the rib-shaped land portions adjacent to each other with one of the circumferential grooves therebetween, the elongate projection portions being formed in an annular shape extending in the tread circumferential direction; the elongate projection portions confronting each other are disposed with a spacing (d) therebetween such that mutually confronting tip surfaces of the confronting elongate projection portions are adapted to be in contact with each other through elastic deformation of the rib-shaped land portions at a time of grounding of the tire; each of the circumferential grooves has formed therein an inside groove space on a radially inner side of the confronting elongate projection portions , and an outside groove space on a radially outer side of the confronting elongate projection portions ; the confronting elongate projection portions have the mutually confronting tip surfaces thereof formed with a plurality of communication recesses providing communication between the outside groove space and the inside groove space , the communication recesses being formed at intervals in the tread circumferential direction; and each of the communication recesses is formed rectilinearly while being oriented in a direction inclined relative to a radial direction in a tire rotational plane, in such a manner that each communication recess has an inside opening communicating with the inside groove space and an outside opening communicating with the outside groove space , the outside opening being located at a position displaced relative to the inside opening in a tire rotational direction at a time of forward travel of a vehicle so that the radially outer side of each communication recess is advanced from the radially inner side of it in the tire rotational direction. <EOS>