Electric press device and differential mechanism

A differential mechanism (9) of an electric press device enabling the securement of the durability of the electric press device while maintaining working accuracy, comprising a nut member (8) threaded with a ball screw shaft (15) rotated by a motor (22) and a connection mechanism (17) fixed to a slide plate (25). The differential mechanism further comprises a frame body (92) having inner wall surfaces formed by recessing the frame body with its opening part facing upward, having a slidable movement groove formed in the bottom surface part inner wall surface, and having the opening part formed in a rigid body, a movable body (91) having a slidable movement groove formed in the rear surface side of its upper plate part having a sloped face and fitted to the opening part of the frame body (92), an wedge-like differential member (94) having, at its lower end part, a first guiding and engaging part slidably engaged with the slidable movement groove formed in the frame body (92), having, at its upper end part, a second guiding and engaging part slidably engaged with the slidable movement groove formed in the rear surface side of the movable body (91), having, on its upper surface, a sloped surface, and slidably fitted to the frame body (92), and a screw shaft (95) moving the differential member (94) by a motor (28).