PURPOSE: To provide a gear pump that gets rid of any turbulent flow of a fluid passing through in an inlet passage of a gear pump body, and has made any deterioration of the fluid so as to be prevented from occurring.

CONSTITUTION: In this gear pump, an inlet passage 3 with an intake port 2 and a gear pump hole, 4 to lee interconnected to this inlet passage 3 both are installed in a gear pump body 1. In this connection, a wall surface of the inlet passage 3 is composed of a curved-face part 3a alone ranging from the intake port 2 to the gear pump hole 4.