A plate cooler for fluids, such as hydraulic oil, having a parallelepiped-shaped package of plate bodies forming spaced-apart fluid channels and air channels interposed between adjacent plate bodies. The plate bodies communicate on their ends with a fluid channel in a distributor box and a collection box. The distributor and collection boxes have an extruded aluminum profile, a continuous fluid channel, and a ribbed body having lateral ribs with continuous guide grooves for mounting elements and receiving slots for the extruded plate body profile. The fluid channels discharge into a collection chamber, communicating with the continuous fluid channel of the ribbed body. The continuous receiving slots for the plate bodies in the distributor box and in the collection box are configured in circular and conical form, and the inserted plate bodies are connected thereto in fluid-tight fashion in a low-temperature adhesive bonding process.