The invention relates to an agrochemicals pre-dilution unit (1) comprising a mixing device (21) that receives and mixes water and agrochemicals. This unit (1) carries out the mixing process by means of a plurality of pumps (18, 20) in fluid communication with the mixing device (21), which sends the prepared mixture to a tank truck through outlet pipes (S). A plurality of containers (2, 3, 4, 5) are installed in the unit (1) and contain agrochemicals that are pumped in a controlled and precise manner to the mixing device (21), allowing a mixture of agrochemicals and water to be prepared with minimum human intervention. Also disclosed is the preparation of the liquid mixture controlled by a PLC, enabling an operator to obtain an accurate mixture without needing to intervene directly in the unit, since the operator can interact with the unit by means of a computer, for example, such that the PLC controls all the devices in the unit (1) in order to prepare the mixture.
