A tire comprising: a tread portion having a designated installing direction to a vehicle to define an outboard tread edge (To) and an inboard tread edge (Ti); the tread portion being provided with a plurality of circumferentially and continuously extending main grooves (3A, 3B, 4A, 4B) comprising an outboard shoulder main groove, an outboard middle main groove, an inboard shoulder main groove and an inboard middle main groove to define an outboard middle portion between the outboard shoulder main groove and the outboard middle main groove, an inboard middle portion between the inboard shoulder main groove and the inboard middle main groove, and a central portion between the outboard middle main groove and the inboard middle main groove; the outboard middle portion being provided with a plurality of outboard middle lateral grooves extending between the outboard shoulder main groove and the outboard middle main groove; and the inboard middle portion being provided with a plurality of inboard middle lateral grooves extending between the inboard shoulder main groove and the inboard middle main groove; characterized by a plurality of outboard middle circumferential sipes each extending between adjacent outboard middle lateral grooves; and the central portion being provided with a circumferentially and continuously extending central sipe; a plurality of outboard middle lateral sipes extending from the outboard shoulder main groove or the outboard middle main groove toward the outboard middle circumferential sipes without reaching the outboard middle circumferential sipes; a plurality of inboard middle circumferential sipes each extending between adjacent inboard middle lateral grooves, and a plurality of inboard middle lateral sipes extending from the inboard shoulder main groove or the inboard middle main groove toward the inboard middle circumferential sipes without reaching the inboard middle circumferential sipes; and the number of the inboard middle lateral sipes being greater than the number of the outboard middle lateral sipes. a tread portion having a designated installing direction to a vehicle to define an outboard tread edge (To) and an inboard tread edge (Ti); the tread portion being provided with a plurality of circumferentially and continuously extending main grooves (3A, 3B, 4A, 4B) comprising an outboard shoulder main groove, an outboard middle main groove, an inboard shoulder main groove and an inboard middle main groove to define an outboard middle portion between the outboard shoulder main groove and the outboard middle main groove, an inboard middle portion between the inboard shoulder main groove and the inboard middle main groove, and a central portion between the outboard middle main groove and the inboard middle main groove; the outboard middle portion being provided with a plurality of outboard middle lateral grooves extending between the outboard shoulder main groove and the outboard middle main groove; and the inboard middle portion being provided with a plurality of inboard middle lateral grooves extending between the inboard shoulder main groove and the inboard middle main groove; characterized by a plurality of outboard middle circumferential sipes each extending between adjacent outboard middle lateral grooves; and the central portion being provided with a circumferentially and continuously extending central sipe; a plurality of outboard middle lateral sipes extending from the outboard shoulder main groove or the outboard middle main groove toward the outboard middle circumferential sipes without reaching the outboard middle circumferential sipes; a plurality of inboard middle circumferential sipes each extending between adjacent inboard middle lateral grooves, and a plurality of inboard middle lateral sipes extending from the inboard shoulder main groove or the inboard middle main groove toward the inboard middle circumferential sipes without reaching the inboard middle circumferential sipes; and the number of the inboard middle lateral sipes being greater than the number of the outboard middle lateral sipes.