A three-dimensional space monitoring device (10) comprises: a learning unit (11) that generates learning results by way of machine learning movement patterns of a first monitor subject (31) and a second monitor subject (32) from first measurement information (31a) of the first monitor subject and second measurement information (32a) of the second monitor subject; a movement space generation unit (13) that generates a first movement space (43) for the first monitor subject (31) and a second movement space (44) for the second monitor subject (32); a distance calculation unit (14) that calculates a first distance (45) from the first monitor subject (31) to the second movement space (44) and a second distance (46) from the second monitor subject (32) to the first movement space (43); and a contact prediction determination unit (15) that determines a distance threshold (L) on the basis of the learning results (D2) and that predicts the possibility of contact between the first monitor subject (31) and the second monitor subject (32) on the basis of the first and second distances (45, 46) and the distance threshold (L). The three-dimensional space monitoring device executes a process based on the possibility of contact.
Three-dimensional space monitoring device, three-dimensional space monitoring method, and three-dimensional space monitoring program