An apparatus and a method for controlling a lock function in a portable terminal are provided. The apparatus includes one or more processors, a display unit for displaying a positional change of an object and an image set including a plurality of objects including the object, and a memory including one or more modules configured to be executed by the one or more processor, including module for displaying the image set, for changing a position of an object of the plurality of objects selected according to a user input, and for controlling the lock function if the selected object is combined with or separated from another object of the plurality of objects according to the positional change. At least one of the selected object and the other object includes a variable area which indicates an extent of the positional change of the selected object or the other object.