In this paper, we treat the image generation task using the autoencoder, a representative latent model. Unlike many studies regularizing the latent variable's distribution by assuming a manually specified prior, we approach the image generation task using an autoencoder by directly estimating the latent distribution. To do this, we introduce 'latent density estimator' which captures latent distribution explicitly and propose its structure. In addition, we propose an incremental learning strategy of latent variables so that the autoencoder learns important features of data by using the structural characteristics of under-complete autoencoder without an explicit regularization term in the objective function. Through experiments, we show the effectiveness of the proposed latent density estimator and the incremental learning strategy of latent variables. We also show that our generative model generates images with improved visual quality compared to previous generative models based on autoencoders.