A drive force transmission device in which a dry clutch for connecting and disconnecting drive force transmission is disposed within a closed space, comprising: the dry clutch comprises: a first clutch plate joined to a clutch hub; a second clutch plate joined to a clutch drum; a frictional face provided on either the first clutch plate or the second clutch plate, a frictional surface thereof being pressed against a surface of the other plate when the clutch is engaged; a cover member having an air intake port for drawing external air into the closed space, and an air venting port for venting an air stream from the closed space into the air; and a splash guard provided so as to cover the air intake port and the air venting port of the cover member, and having an opening for drawing in external air through the air intake port and venting an air stream from the air venting port; a damper for attenuating variations in drive force from the drive source being provided at a position outside the splash guard; and in the splash guard, a side guard surface located upstream with respect to the rotational direction of the damper being closed, and the opening being provided in a side guard surface located downstream with respect to the rotational direction of the damper. the dry clutch comprises: a first clutch plate joined to a clutch hub; a second clutch plate joined to a clutch drum; a frictional face provided on either the first clutch plate or the second clutch plate, a frictional surface thereof being pressed against a surface of the other plate when the clutch is engaged; a cover member having an air intake port for drawing external air into the closed space, and an air venting port for venting an air stream from the closed space into the air; and a splash guard provided so as to cover the air intake port and the air venting port of the cover member, and having an opening for drawing in external air through the air intake port and venting an air stream from the air venting port; a damper for attenuating variations in drive force from the drive source being provided at a position outside the splash guard; and in the splash guard, a side guard surface located upstream with respect to the rotational direction of the damper being closed, and the opening being provided in a side guard surface located downstream with respect to the rotational direction of the damper. a first clutch plate joined to a clutch hub; a second clutch plate joined to a clutch drum; a frictional face provided on either the first clutch plate or the second clutch plate, a frictional surface thereof being pressed against a surface of the other plate when the clutch is engaged; a cover member having an air intake port for drawing external air into the closed space, and an air venting port for venting an air stream from the closed space into the air; and a splash guard provided so as to cover the air intake port and the air venting port of the cover member, and having an opening for drawing in external air through the air intake port and venting an air stream from the air venting port; a damper for attenuating variations in drive force from the drive source being provided at a position outside the splash guard; and in the splash guard, a side guard surface located upstream with respect to the rotational direction of the damper being closed, and the opening being provided in a side guard surface located downstream with respect to the rotational direction of the damper.