A differential device (5) of an electric actuator (1) includes a driving rotary body (2), a driven rotary body (3), and a planetary rotary body (52). A first speed reducer (5a) is formed between the planetary rotary body (52) and the driving rotary body (2). A second speed reducer (5b) is formed between the planetary rotary body (52) and the driven rotary body (3). The electric actuator (1) includes a first bearing (53) configured to support the planetary rotary body (52) on an inner side of a rotor (42) of an electric motor (4), and a second bearing (54) configured to support the planetary rotary body (52) at a position shifted in an axial direction so as to be prevented from overlapping the rotor (42). The second bearing (54) is formed of a deep-groove ball bearing.