A saddle-riding type vehicle comprising: an engine; a supercharger to pressurize and supply an intake air to the engine; a throttle body to control the amount of intake air to be supplied to an air intake port of the engine; and an air intake chamber disposed downstream of a discharge port of the supercharger and upstream of the throttle body, the air intake chamber being disposed between the supercharger and a cylinder head of the engine, in which an inlet is formed in the rear portion of the air intake chamber and an outlet is formed in the front portion of the air intake chamber, and the chamber comprises: a confronting portion having the outlet of the air intake chamber and facing the throttle body; a connecting portion to connect the confronting portion and the discharge port of the supercharger, the connecting portion having an outlet side opening that is set to be larger than an inlet side opening; and the connecting portion has a transverse width that gradually increases from the inlet side opening towards the outlet side opening, characterised in that - the supercharger is disposed above a crankcase of the engine and rearwardly of a cylinder block of the engine; - the supercharger is a centrifugal type supercharger that is driven by a driving power transmitted from the engine through a mechanical power transmitting system, and has a rotational axis that extends in a vehicle widthwise direction above a rear portion of the crankcase; - the air intake chamber extends, in a longitudinal direction of the vehicle, from a rear end of a crankcase of the engine to a region forwardly of the throttle body; - the air intake chamber is disposed at a location diagonally upwardly and forwardly of the supercharger and diagonally upwardly and rearwardly of the cylinder head and the throttle body; - the outlet side opening of the connecting portion is so formed as to have a widthwise dimension of the transverse width and a longitudinal dimension perpendicular to the vehicle widthwise direction, both which are greater than those of the inlet opening of the connecting portion; - the connecting portion has an upper surface inclined downwardly in a rearward direction; and - the air intake chamber has a front wall protruding to be positioned forwardly of a throttle body mounting portion defined in the confronting portion. an engine; a supercharger to pressurize and supply an intake air to the engine; a throttle body to control the amount of intake air to be supplied to an air intake port of the engine; and an air intake chamber disposed downstream of a discharge port of the supercharger and upstream of the throttle body, the air intake chamber being disposed between the supercharger and a cylinder head of the engine, in which an inlet is formed in the rear portion of the air intake chamber and an outlet is formed in the front portion of the air intake chamber, and the chamber comprises: a confronting portion having the outlet of the air intake chamber and facing the throttle body; a connecting portion to connect the confronting portion and the discharge port of the supercharger, the connecting portion having an outlet side opening that is set to be larger than an inlet side opening; and the connecting portion has a transverse width that gradually increases from the inlet side opening towards the outlet side opening, a confronting portion having the outlet of the air intake chamber and facing the throttle body; a connecting portion to connect the confronting portion and the discharge port of the supercharger, the connecting portion having an outlet side opening that is set to be larger than an inlet side opening; and the connecting portion has a transverse width that gradually increases from the inlet side opening towards the outlet side opening, - the supercharger is disposed above a crankcase of the engine and rearwardly of a cylinder block of the engine; - the supercharger is a centrifugal type supercharger that is driven by a driving power transmitted from the engine through a mechanical power transmitting system, and has a rotational axis that extends in a vehicle widthwise direction above a rear portion of the crankcase; - the air intake chamber extends, in a longitudinal direction of the vehicle, from a rear end of a crankcase of the engine to a region forwardly of the throttle body; - the air intake chamber is disposed at a location diagonally upwardly and forwardly of the supercharger and diagonally upwardly and rearwardly of the cylinder head and the throttle body; - the outlet side opening of the connecting portion is so formed as to have a widthwise dimension of the transverse width and a longitudinal dimension perpendicular to the vehicle widthwise direction, both which are greater than those of the inlet opening of the connecting portion; - the connecting portion has an upper surface inclined downwardly in a rearward direction; and - the air intake chamber has a front wall protruding to be positioned forwardly of a throttle body mounting portion defined in the confronting portion.