Abstract: A method of producing a fine particle dispersion characterized by having a dispersing step where, after fine particles have been sucked into a dispersing medium to prepare a suspension by a suction type stirring machine and bubbles have been removed from the suspension by a bubble removing means, the suspension is pressurized and introduced from the opposite directions so as to collide with each other, thereby dispersing the suspension.

Abstract: The present invention provides a high pressure pump (1), which comprises an electric motor (2) having a through-hole in axial direction on a rotation shaft (5), a thrust transmission shaft (8) engaged with threads of a rotation nut (6) operated by rotation of the motor, passing through the through-hole and performing linear reciprocal movement, plungers (9a, 9b) performing reciprocal movement in cylinders and connected to at least one end of the thrust transmission shaft (8), and a stress-strain sensor (16) provided on at least one of the plunger or the thrust transmission shaft.