An image pickup apparatus that is capable of obtaining a composite image having a sufficient desired effect without considering the required number of pickup images by a user. An obtaining unit obtains an image pickup condition of an object. A determination unit determines a termination condition according to the image pickup condition. An image pickup unit picks up an image of the object. An image composition unit generates a composite image of a series of every image of the object picked up by the image pickup unit whenever any image of the object is picked up by the image pickup unit. A feature-amount calculation unit calculates a feature amount of the composite image whenever the composite image concerned is generated. An output unit outputs the composite image as a final composite image of which the feature amount calculated by the feature-amount calculation unit satisfies the termination condition.