An electric folding device for exterior rear-view mirror of a vehicle comprising: a housing, connected with a mirror base plate; a base, the base is fixedly connected with the housing, and a base cam assembly (2.1) is disposed on a lower end surface of the base; a seat, the seat is fixed on a mirror bracket, and a seat cam assembly (3.1) is disposed at an upper end of the seat; the base cam assembly (2.1) and the seat cam assembly (3.1) are in engaged state in an initial state; a mounting shaft, the mounting shaft is fixedly connected with the seat, and the base and the housing rotate around an axis of the mounting shaft relative to the seat, and a spring is disposed on the mounting shaft; an electric drive unit, comprising a motor (4.1), a transmission assembly (4.2) and a drive gear (4.3) disposed in an inner chamber of the housing; wherein it further comprises: a centralized connection piece, and the centralized connection piece is provided with a mounting portion (5.1) for the drive gear (4.3) to slide circumferentially; a limiting seat (5.2) is integrally disposed on an upper part of the mounting portion (5.1), characterized in that the spring is abutted against an upper end of the limiting seat (5.2), and the drive gear (4.3) is abutted between the limiting seat (5.2) and the base; a first reserved gap is formed between the limiting seat (5.2) and the drive gear (4.3) with a plurality of limiting convex blocks (4.3.2, 5.4) abutting against each other; a second reserved gap is formed between the base and the drive gear (4.3) with a plurality of limiting convex blocks (4.3.3, 2.2) abutting against each other; driven by the electric drive unit, the abutting of each group of limiting convex blocks (4.3.2, 4.3.3; 5.4, 2.2) is released by sliding the drive gear (4.3) circumferentially along the mounting portion (5.1) of the centralized connection piece, and driving the base cam assembly (2.1) to slide relative to the seat cam assembly (3.1), and the second reserved gap is firstly eliminated and then the first reserved gap is eliminated until the base cam assembly (2.1) is opposed to the seat cam assembly (3.1) to realize an upward lift of the base. a housing, connected with a mirror base plate; a base, the base is fixedly connected with the housing, and a base cam assembly (2.1) is disposed on a lower end surface of the base; a seat, the seat is fixed on a mirror bracket, and a seat cam assembly (3.1) is disposed at an upper end of the seat; the base cam assembly (2.1) and the seat cam assembly (3.1) are in engaged state in an initial state; a mounting shaft, the mounting shaft is fixedly connected with the seat, and the base and the housing rotate around an axis of the mounting shaft relative to the seat, and a spring is disposed on the mounting shaft; an electric drive unit, comprising a motor (4.1), a transmission assembly (4.2) and a drive gear (4.3) disposed in an inner chamber of the housing; wherein it further comprises: a centralized connection piece, and the centralized connection piece is provided with a mounting portion (5.1) for the drive gear (4.3) to slide circumferentially; a limiting seat (5.2) is integrally disposed on an upper part of the mounting portion (5.1), characterized in that the spring is abutted against an upper end of the limiting seat (5.2), and the drive gear (4.3) is abutted between the limiting seat (5.2) and the base; a first reserved gap is formed between the limiting seat (5.2) and the drive gear (4.3) with a plurality of limiting convex blocks (4.3.2, 5.4) abutting against each other; a second reserved gap is formed between the base and the drive gear (4.3) with a plurality of limiting convex blocks (4.3.3, 2.2) abutting against each other; driven by the electric drive unit, the abutting of each group of limiting convex blocks (4.3.2, 4.3.3; 5.4, 2.2) is released by sliding the drive gear (4.3) circumferentially along the mounting portion (5.1) of the centralized connection piece, and driving the base cam assembly (2.1) to slide relative to the seat cam assembly (3.1), and the second reserved gap is firstly eliminated and then the first reserved gap is eliminated until the base cam assembly (2.1) is opposed to the seat cam assembly (3.1) to realize an upward lift of the base. a centralized connection piece, and the centralized connection piece is provided with a mounting portion (5.1) for the drive gear (4.3) to slide circumferentially; a limiting seat (5.2) is integrally disposed on an upper part of the mounting portion (5.1), characterized in that the spring is abutted against an upper end of the limiting seat (5.2), and the drive gear (4.3) is abutted between the limiting seat (5.2) and the base; a first reserved gap is formed between the limiting seat (5.2) and the drive gear (4.3) with a plurality of limiting convex blocks (4.3.2, 5.4) abutting against each other; a second reserved gap is formed between the base and the drive gear (4.3) with a plurality of limiting convex blocks (4.3.3, 2.2) abutting against each other; driven by the electric drive unit, the abutting of each group of limiting convex blocks (4.3.2, 4.3.3; 5.4, 2.2) is released by sliding the drive gear (4.3) circumferentially along the mounting portion (5.1) of the centralized connection piece, and driving the base cam assembly (2.1) to slide relative to the seat cam assembly (3.1), and the second reserved gap is firstly eliminated and then the first reserved gap is eliminated until the base cam assembly (2.1) is opposed to the seat cam assembly (3.1) to realize an upward lift of the base.