To control a maximum injection rate to an optimal value in an altitude where the atmosphere is reduced by constituting the relation between the displacement of a pressure pin and the maximum rotational displacement of a tension arm in a non-linear.

The upper part of a bellows 1 which is expanded and contracted in a longitudinal direction by change of the atmosphere is fixed to the main body of a fuel injection pump 15, and its lower part is connected to a bush rod 2 having a taper surface 2a. The bush rod 2 is moved vertically by expanding and contracting the bellows 1, a pressure pin 3 which abuts on one end of the taper surface 2a is moved in left and right directions, a spill ring 8 is displaced in an axial direction through a control arm 4, a tension arm 6, and the like, and a fuel injection rate is regulated. At this time, an abutting surface 4a on the top end of the pressure pin 3 of one end of the arm 4 is formed in a flange shaped bending surface, and thereby, it is changed in a bending line shape to the characteristic of a maximum injection rate of the atmosphere so as to control the maximum injection rate to an optimal value in an altitude.