A centrifugal pump apparatus including a housing having first and second chambers (7, 8) partitioned from each other by a dividing wall, an impeller rotatably provided in said first chamber along said dividing wall, for delivering fluid by centrifugal force during rotation, and a drive unit (18 to 20) provided in said second chamber, for driving said impeller to rotate with said dividing wall being interposed, the centrifugal pump apparatus comprising: a first magnetic element (15a, 15b) provided in one surface of said impeller; a second magnetic element (16a, 16b) provided in an inner wall of said first chamber facing the one surface of said impeller, for attracting said first magnetic element (15a, 15b); a third magnetic element provided in the other surface of said impeller and attracted by said drive unit (18 to 20); and a fluid outlet port for allowing said fluid to flow to the outside of said housing from an opening provided in a sidewall of said first chamber, wherein during rotation of said impeller, first attractive force acting on between said first and second magnetic elements (15a, 15b; 16a, 16b) and second attractive force acting on between said third magnetic element and said drive unit (18 to 20) are balanced with each other substantially in a center of a movable range of said impeller in said first chamber, a first groove for hydrodynamic bearing is formed in the one surface of said impeller or in the inner wall of said first chamber facing the one surface and a second groove for hydrodynamic bearing is formed in the other surface of said impeller or in said dividing wall facing the other surface, at least one of said first and second magnetic elements (15a, 15b; 16a, 16b) is formed annularly around a rotation centerline of said impeller, and wherein said second magnetic element (16a, 16b) is a permanent magnet formed annularly around the rotation centerline of said impeller, the centrifugal pump apparatus being characterised in that a value of attractive force between said first and second magnetic elements (15a, 15b; 16a, 16b) on said opening side is set to be different from a value of attractive force between said first and second magnetic elements (15a, 15b; 16a, 16b) on an opposite side of said opening such that said impeller becomes parallel to said dividing wall during rotation of said impeller and a thickness of said second magnetic element (16a, 16b) on said opening side is smaller than a thickness of said second magnetic element (16a, 16b) on the opposite side of said opening. a first magnetic element (15a, 15b) provided in one surface of said impeller; a second magnetic element (16a, 16b) provided in an inner wall of said first chamber facing the one surface of said impeller, for attracting said first magnetic element (15a, 15b); a third magnetic element provided in the other surface of said impeller and attracted by said drive unit (18 to 20); and a fluid outlet port for allowing said fluid to flow to the outside of said housing from an opening provided in a sidewall of said first chamber, wherein during rotation of said impeller, first attractive force acting on between said first and second magnetic elements (15a, 15b; 16a, 16b) and second attractive force acting on between said third magnetic element and said drive unit (18 to 20) are balanced with each other substantially in a center of a movable range of said impeller in said first chamber, a first groove for hydrodynamic bearing is formed in the one surface of said impeller or in the inner wall of said first chamber facing the one surface and a second groove for hydrodynamic bearing is formed in the other surface of said impeller or in said dividing wall facing the other surface, at least one of said first and second magnetic elements (15a, 15b; 16a, 16b) is formed annularly around a rotation centerline of said impeller, and wherein said second magnetic element (16a, 16b) is a permanent magnet formed annularly around the rotation centerline of said impeller, the centrifugal pump apparatus being characterised in that a value of attractive force between said first and second magnetic elements (15a, 15b; 16a, 16b) on said opening side is set to be different from a value of attractive force between said first and second magnetic elements (15a, 15b; 16a, 16b) on an opposite side of said opening such that said impeller becomes parallel to said dividing wall during rotation of said impeller and a thickness of said second magnetic element (16a, 16b) on said opening side is smaller than a thickness of said second magnetic element (16a, 16b) on the opposite side of said opening.