A scroll compressor, comprising: a casing; a driving motor provided at an inner space of the casing; a rotation shaft coupled to a rotor of the driving motor, and rotated together with the rotor; a fixed scroll having a fixed plate portion formed in a disc shape, a scroll side wall portion formed at an edge of the fixed plate portion, and a fixed wrap formed on an upper surface of the fixed plate portion; and an orbiting scroll having an orbiting wrap so as to form a compression chamber of a suction chamber, an intermediate pressure chamber and a discharge chamber, by being engaged with the fixed wrap, and having a rotation shaft coupling portion for coupling the rotation shaft thereto in a penetrating manner, wherein the rotation shaft coupling portion is extended from the orbiting wrap so as to form an inner end of the orbiting wrap, wherein a discharge opening is formed at a central part of the fixed plate portion, communicated with a discharge chamber and through which a compressed refrigerant is discharged, wherein a refrigerant passage is penetratingly-formed at the scroll side wall portion, wherein the fixed scroll is formed of cast-iron, and the orbiting scroll is formed of aluminum wherein in a state where a center of the fixed scroll and a center of the orbiting scroll are consistent with each other, an interval (G1, G2, G3) between the fixed wrap and the orbiting wrap is gradually increased towards the suction chamber (Vs) from the discharge chamber (Vd), wherein a wrap thickness (t1, t2, t3) of the orbiting wrap is gradually decreased towards the suction chamber from the discharge chamber, and a wrap thickness of the fixed wrap is uniform towards the suction chamber from the discharge chamber. a casing; a driving motor provided at an inner space of the casing; a rotation shaft coupled to a rotor of the driving motor, and rotated together with the rotor; a fixed scroll having a fixed plate portion formed in a disc shape, a scroll side wall portion formed at an edge of the fixed plate portion, and a fixed wrap formed on an upper surface of the fixed plate portion; and an orbiting scroll having an orbiting wrap so as to form a compression chamber of a suction chamber, an intermediate pressure chamber and a discharge chamber, by being engaged with the fixed wrap, and having a rotation shaft coupling portion for coupling the rotation shaft thereto in a penetrating manner, wherein the rotation shaft coupling portion is extended from the orbiting wrap so as to form an inner end of the orbiting wrap, wherein a discharge opening is formed at a central part of the fixed plate portion, communicated with a discharge chamber and through which a compressed refrigerant is discharged, wherein a refrigerant passage is penetratingly-formed at the scroll side wall portion, wherein the fixed scroll is formed of cast-iron, and the orbiting scroll is formed of aluminum wherein in a state where a center of the fixed scroll and a center of the orbiting scroll are consistent with each other, an interval (G1, G2, G3) between the fixed wrap and the orbiting wrap is gradually increased towards the suction chamber (Vs) from the discharge chamber (Vd), wherein a wrap thickness (t1, t2, t3) of the orbiting wrap is gradually decreased towards the suction chamber from the discharge chamber, and a wrap thickness of the fixed wrap is uniform towards the suction chamber from the discharge chamber.