The physicochemical properties of chocolate mass with 85% cocoa content and 3%, 5%, and 10% of Arthrospira platensis have been studied. The algae were grown into a bioreactor in Varvara, Bulgaria. The present work aims to create an innovative chocolate product with appropriate physicochemical properties and organoleptic characteristics, contributing to the healthy nutrition of consumers. To achieve this goal, a technological scheme was developed for obtaining chocolate mass with Arthrospira platensis. Rheological, X-ray structural, and sensory analyses were performed. Data from reflective microscopy and fluorescence spectroscopy were also obtained. X-ray analysis shows peaks of crystalline sucrose and cocoa. In addition to these peaks in the X-ray diffraction pattern of the sample with 10% Arthrospira platensis content, some peaks may be due to complex crystals of the protein structure of freshwater algae. The rheological curves of the samples show that the studied systems are non-Newtonian fluids. Increasing the concentration of Arthrospira platensis does not affect the stickiness, softness, and hardness. According to sensory analysis, the samples with 5% Arthrospira platensis have a pronounced sweet taste, and those with 3% - a cocoa taste. Reflective microscope images were taken to examine the fracture section.