PURPOSE: To provide a heat sink fan where a heat sink and a housing can be removed for maintenance or replacement, and besides the heat sink and the housing are not separated easily by the external force such as shock, etc.

CONSTITUTION: This heat sink fan is equipped with a box-shaped heat sink 1 for heat radiation, whose end side is open, and a housing 2 for assembling a fan motor, which is attached in cover shape to the margin of the opening of the heat sink 1. A locking recess 30 in step shape is made at the diagonal part of either the heat sink 1 or the housing 2. And, a locking claw 23 capable of being locked with momentum in the locking recess 30 by bringing the heat sink 1 and the housing 2 close to each other and besides capable of being separated with momentum from the locking recess 30 by rotating the heat sink 1 and the housing 2 relatively is projected at the other diagonal.