A heat-dissipation device for dissipating heat from a circuit board and the circuit board having a surface, the heat-dissipation device comprising: a first fan, blades of said first fan rotating around a first rotating axis, and the first rotating axis and the surface forming an acute angle; a second fan, blades of said second fan rotating around a second rotating axis, and the second rotating axis and the surface forming an acute angle; and a third fan, blades of said third fan rotating around a third rotating axis, the third rotating axis and the surface forming an acute angle, and said second fan being disposed between said first fan and said third fan, wherein orthogonal projections (100c, 320c) of the second rotating axis and of the first rotating axis on the surface are perpendicular to one another, and the orthogonal projections (320c, 330c) of the second rotating axis and of the third rotating axis are perpendicular to one another; and the intersection between the first rotating axis and the circuit board heading the direction away from said second fan, and the intersection between the third rotating axis and the circuit board heading the direction away from said second fan; the heat-dissipation device further comprising a heat sink disposed between said first fan, said second fan, said third fan and the surface of the circuit board, said heat sink including a plurality of first fins that are parallel in arrangement, a plurality of second fins that are parallel in arrangement and a plurality of third fins that are parallel in arrangement, the first fins being parallel to the orthogonal projection of the first rotating axis, the second fins being parallel to the orthogonal projection of the second rotating axis, and the third fins being parallel to the orthogonal projection of the third rotating axis; wherein air flows of said first fan and said third fan flow respectively through the passageways formed by the first fins and the third fins away from said second fan, and air flows of said second fan flow through the passageways formed by the second fins away from said first fan and said third fan. a first fan, blades of said first fan rotating around a first rotating axis, and the first rotating axis and the surface forming an acute angle; a second fan, blades of said second fan rotating around a second rotating axis, and the second rotating axis and the surface forming an acute angle; and a third fan, blades of said third fan rotating around a third rotating axis, the third rotating axis and the surface forming an acute angle, and said second fan being disposed between said first fan and said third fan, wherein orthogonal projections (100c, 320c) of the second rotating axis and of the first rotating axis on the surface are perpendicular to one another, and the orthogonal projections (320c, 330c) of the second rotating axis and of the third rotating axis are perpendicular to one another; and the intersection between the first rotating axis and the circuit board heading the direction away from said second fan, and the intersection between the third rotating axis and the circuit board heading the direction away from said second fan; the heat-dissipation device further comprising a heat sink disposed between said first fan, said second fan, said third fan and the surface of the circuit board, said heat sink including a plurality of first fins that are parallel in arrangement, a plurality of second fins that are parallel in arrangement and a plurality of third fins that are parallel in arrangement, the first fins being parallel to the orthogonal projection of the first rotating axis, the second fins being parallel to the orthogonal projection of the second rotating axis, and the third fins being parallel to the orthogonal projection of the third rotating axis; wherein air flows of said first fan and said third fan flow respectively through the passageways formed by the first fins and the third fins away from said second fan, and air flows of said second fan flow through the passageways formed by the second fins away from said first fan and said third fan.