A swash plate type variable displacement compressor comprising: a housing (1; 201) in which a suction chamber (27a, 27b; 34), a discharge chamber (29a, 29b; 36), a swash plate chamber (33; 225), and a cylinder bore (21a, 23a; 221a) are formed; a drive shaft (3; 203) that is rotationally supported by the housing (1; 201); a swash plate (5; 205) that is rotational in the swash plate chamber (33; 225) by rotation of the drive shaft (3; 203); a link mechanism (7; 207) arranged between the drive shaft (3; 203) and the swash plate (5; 205), wherein the link mechanism (7; 207) allows change of an inclination angle of the swash plate (5; 205) with respect to a direction perpendicular to a rotation axis of the drive shaft (3; 203); a piston (9; 209) reciprocally received in the cylinder bore (21a, 23a; 221a); a conversion mechanism (11a, 11b; 211a, 211b) that causes the piston (9; 209) to reciprocate in the cylinder bore (21a, 23a; 221a) by a stroke corresponding to the inclination angle of the swash plate (5; 205) through rotation of the swash plate (5; 205); an actuator (13; 213) that changes the inclination angle of the swash plate (5; 205); and a control mechanism (15; 16) that controls the actuator (13; 213), the swash plate type variable displacement compressor being characterized in that the housing (1; 201) has a pressure regulation chamber (31; 32, 32a, 32b), the actuator (13; 213) includes a fixed body that is located in the swash plate chamber (33; 225) and fixed to the drive shaft (3; 203), a movable body (13a; 213a) that is provided on the drive shaft (3; 203) and is capable of changing the inclination angle of the swash plate (5; 205) by moving along the rotation axis of the drive shaft (3; 203), and a control pressure chamber (13c; 213b) defined by the fixed body and the movable body (13a; 213a), wherein the volume of the control pressure chamber (13c; 213b) is changed by the pressure of refrigerant in the discharge chamber (29a, 29b; 36) to move the movable body (13a; 213a), the control mechanism (15; 16) includes a control passage (3a, 3b, 15a, 15b, 16a, 16b; 203a, 203b) that connects together the discharge chamber (29a, 29b; 36), the pressure regulation chamber (31; 32, 32a, 32b), and the control pressure chamber (13c; 213b), and a control valve (15c; 16c) that adjusts an opening degree of the control passage (3a, 3b, 15a, 15b, 16a, 16b; 203a, 203b) to change the pressure in the control pressure chamber (13c; 213b) to allow the movable body (13a; 213a) to move, the refrigerant in the discharge chamber (29a, 29b; 36) flows into the control pressure chamber (13c; 213b) via the pressure regulation chamber (31; 32, 32a, 32b), and the pressure regulation chamber (31; 32, 32a, 32b) functions as a muffler that reduces pulsation of the refrigerant. a housing (1; 201) in which a suction chamber (27a, 27b; 34), a discharge chamber (29a, 29b; 36), a swash plate chamber (33; 225), and a cylinder bore (21a, 23a; 221a) are formed; a drive shaft (3; 203) that is rotationally supported by the housing (1; 201); a swash plate (5; 205) that is rotational in the swash plate chamber (33; 225) by rotation of the drive shaft (3; 203); a link mechanism (7; 207) arranged between the drive shaft (3; 203) and the swash plate (5; 205), wherein the link mechanism (7; 207) allows change of an inclination angle of the swash plate (5; 205) with respect to a direction perpendicular to a rotation axis of the drive shaft (3; 203); a piston (9; 209) reciprocally received in the cylinder bore (21a, 23a; 221a); a conversion mechanism (11a, 11b; 211a, 211b) that causes the piston (9; 209) to reciprocate in the cylinder bore (21a, 23a; 221a) by a stroke corresponding to the inclination angle of the swash plate (5; 205) through rotation of the swash plate (5; 205); an actuator (13; 213) that changes the inclination angle of the swash plate (5; 205); and a control mechanism (15; 16) that controls the actuator (13; 213), the swash plate type variable displacement compressor being characterized in that the housing (1; 201) has a pressure regulation chamber (31; 32, 32a, 32b), the actuator (13; 213) includes a fixed body that is located in the swash plate chamber (33; 225) and fixed to the drive shaft (3; 203), a movable body (13a; 213a) that is provided on the drive shaft (3; 203) and is capable of changing the inclination angle of the swash plate (5; 205) by moving along the rotation axis of the drive shaft (3; 203), and a control pressure chamber (13c; 213b) defined by the fixed body and the movable body (13a; 213a), wherein the volume of the control pressure chamber (13c; 213b) is changed by the pressure of refrigerant in the discharge chamber (29a, 29b; 36) to move the movable body (13a; 213a), the control mechanism (15; 16) includes a control passage (3a, 3b, 15a, 15b, 16a, 16b; 203a, 203b) that connects together the discharge chamber (29a, 29b; 36), the pressure regulation chamber (31; 32, 32a, 32b), and the control pressure chamber (13c; 213b), and a control valve (15c; 16c) that adjusts an opening degree of the control passage (3a, 3b, 15a, 15b, 16a, 16b; 203a, 203b) to change the pressure in the control pressure chamber (13c; 213b) to allow the movable body (13a; 213a) to move, the refrigerant in the discharge chamber (29a, 29b; 36) flows into the control pressure chamber (13c; 213b) via the pressure regulation chamber (31; 32, 32a, 32b), and the pressure regulation chamber (31; 32, 32a, 32b) functions as a muffler that reduces pulsation of the refrigerant.