The invention relates to an imaging device comprising a multi-main body focusing mode, a lens module, a selection module, a focusing module and a calculating module, wherein the lens module comprises a lens and a motor for driving the lens; the selection module is used for selecting the multi-main body focusing mode according to the input of a user and selecting at least two main bodies in a shot picture; the focusing module is used for controlling the motor to drive the lens to respectively focus the at least two main bodies so as to obtain at least two focusing motor steps corresponding to the at least two main bodies; the calculating module is used for calculating the average vale of the at least two focusing motor steps to obtain the averaged focusing motor steps; and the focusing module controls the lens module to focus the at least two main bodies in the shot picture according to the averaged focusing motor steps. In addition, the invention also relates to a focusing method. The imaging device can focus after freely selecting the plurality of main bodies to shoot images with the plurality of clearer main bodies.