A variable displacement compressor comprising: a housing (12,13;82,83) defining a crank chamber (14; 84); a rotary shaft (15; 85) rotatably supported by the housing (12, 13; 82, 83); a swash plate (17; 87) accommodated in the crank chamber (14; 84), tiltably supported by the rotary shaft (15; 85) and rotating integrally with the rotary shaft (15; 85); a suction-pressure region including a suction chamber (26; 96) and a suction passage (32; 102) through which refrigerant gas under a pressure lower than a discharge pressure passes to the suction chamber (26; 96); a suction throttle valve (40; 110) having a valve body (50, 55) for adjusting the opening of the suction passage (32; 102), the suction throttle valve (40; 110) arranged in the suction passage (32; 102) and defining an upstream suction-pressure region located upstream of the suction throttle valve (40; 110) and a downstream suction-pressure region located downstream of the suction throttle valve (40; 110) in the suction-pressure region, characterised in that an oil reservoir (35; 72; 105) storing lubricating oil separated from refrigerant gas under a discharge pressure in an oil separator; a lubricating oil passage (37; 71; 107) connecting the oil reservoir (35; 72; 105) to the upstream suction-pressure region, wherein a throttle mechanism is provided in the lubricating oil passage (37; 71; 107); and a gas flow passage (30; 100) connecting the crank chamber (14; 84) to the suction chamber (26; 96), wherein a communication passage (39; 109; 139) connects the lubricating oil passage (37; 71; 107) to at least one of the downstream suction-pressure region, the gas flow passage (30; 100) and the crank chamber (14; 84), and the throttle mechanism is provided in the lubricating oil passage (37; 71; 107) between the oil reservoir (35, 72, 105) and a position where the communication passage (39; 109; 139) connects to the lubricating oil passage (37; 71; 107). a housing (12,13;82,83) defining a crank chamber (14; 84); a rotary shaft (15; 85) rotatably supported by the housing (12, 13; 82, 83); a swash plate (17; 87) accommodated in the crank chamber (14; 84), tiltably supported by the rotary shaft (15; 85) and rotating integrally with the rotary shaft (15; 85); a suction-pressure region including a suction chamber (26; 96) and a suction passage (32; 102) through which refrigerant gas under a pressure lower than a discharge pressure passes to the suction chamber (26; 96); a suction throttle valve (40; 110) having a valve body (50, 55) for adjusting the opening of the suction passage (32; 102), the suction throttle valve (40; 110) arranged in the suction passage (32; 102) and defining an upstream suction-pressure region located upstream of the suction throttle valve (40; 110) and a downstream suction-pressure region located downstream of the suction throttle valve (40; 110) in the suction-pressure region, characterised in that an oil reservoir (35; 72; 105) storing lubricating oil separated from refrigerant gas under a discharge pressure in an oil separator; a lubricating oil passage (37; 71; 107) connecting the oil reservoir (35; 72; 105) to the upstream suction-pressure region, wherein a throttle mechanism is provided in the lubricating oil passage (37; 71; 107); and a gas flow passage (30; 100) connecting the crank chamber (14; 84) to the suction chamber (26; 96), wherein a communication passage (39; 109; 139) connects the lubricating oil passage (37; 71; 107) to at least one of the downstream suction-pressure region, the gas flow passage (30; 100) and the crank chamber (14; 84), and the throttle mechanism is provided in the lubricating oil passage (37; 71; 107) between the oil reservoir (35, 72, 105) and a position where the communication passage (39; 109; 139) connects to the lubricating oil passage (37; 71; 107).