This paper focuses on improving the performance of the forward-forward algorithm, which was proposed to overcome the limitations of the backpropagation algorithm, such as its biological impracticality and global error propagation. Existing forward-forward algorithms have been significantly inferior to the backpropagation algorithm in terms of accuracy and inference efficiency. In this study, we propose the FAUST (Forward-Forward Algorithm Unified with Similarity-based Tuplet loss) algorithm, which integrates a similarity learning framework into the forward-forward algorithm, eliminating the need for multiple forward propagation passes during the inference process. Experimental results using the MNIST, Fashion-MNIST, and CIFAR-10 datasets demonstrate that FAUST significantly improves accuracy compared to existing forward-forward algorithms, narrowing the performance gap with the backpropagation algorithm. Specifically, on the CIFAR-10 dataset, using a simple multilayer perceptron architecture, we achieve an accuracy of 56.22%, approaching the 57.63% accuracy of the backpropagation algorithm.