The invention relates to an arrangement for retroreflection of an optical ray using triple prisms. Six to ten triple prisms (1, 2, 3, 131, 132, 133) arm provided with triangular light entry surfaces, wherein the side faces of adjacent triple prisms are in contact. This results in continuous retroreflection at a high level of intensity for one angle area, of 360.degree.. When used in particular in geodesy or in construction surveying, this all-round reflector provides a high degree of measurement accuracy for angles and distances from any direction on which a bearing is taken. Alignment towards a surveying instrument is therefore not necessary. Measurement of short distances is also definite and reliable. The all-round reflector is particularly advantageous for automatic surveying, since, irrespective of its orientation, it can be automatically tracked by a motorised surveying instrument.