Provided is an imaging device which simplifies an assembling adjustment so as to reduce the manufacturing time and cost, wherein second lens L2 driven by actuator 30 is brought into contact with first lens L1 and third lens L3 so that a hyper-focal position or an infinite position as a reference focal position, and close-up position are accurately positioned, that is, it is possible to perform assembling without adjustment and effectively reduce the number of manufacturing steps.