In an electric motorized hinge apparatus, a biasing means maintains a concavo-convex engagement state between a third rotating member and a second engagement portion in a second rotating member, and thus the second rotating member rotates to follow the third rotating member. Furthermore, the biasing means maintains a concavo-convex holding state between a first engagement portion in the second rotating member and a first rotating member, and thus the first rotating member rotates to follow the second rotating member. Furthermore, as the first rotating member rotates, a lid portion rotates to follow it. During manual rotation of the lid portion, a motor is maintained in an off state and the second rotating member is kept at a stop by a lock means. Therefore, the engagement state at the first concavo-convex engagement part is released by the manual rotation of the lid portion, so that the lid portion can be freely rotated by hand.