We report on the design and performance of a hollow-cathode discharge continuous wave He-Cd+ laser module, which is capable of simultaneously delivering stable, milliwatt power output at the three primary spectral lines blue, green and red. A mixture of these lines can result in a wide band of colours, including white light. The laser can be formed from one or more laser modules. A module consists of two anodes with a hollow cathode located between them. Two long, narrow cylinders (50 mm long, 4 mm in diameter) separated by a wider cylinder (10 mm long, 10 mm in diameter) are made in the hollow cathode. The narrow cylinders serve as hollow cathodes, while the wider cylinder efficiently stabilizes the discharges in the narrow cathode cylinders, making them spatially similar. Owing to this particular cathode design the laser module, with a 10 cm active length, stably and effectively lased at seven wavelengths in blue ( lambda =441.6 nm, 3 mW), green ( lambda =533.7 nm, 0.3 mW; lambda =537.8 nm, 0.4 mW), red ( lambda =635.5 and 636.0 nm, total 0.2 mW), and infrared ( lambda =723.8 and 728.4 nm, total 0.1 mW). The optimum He pressure, Cd vapour pressure and cathode current were 8 mbar, 0.01 mbar (corresponding to a cathode temperature of 533 K), and 260 mA, respectively. The short- and long-term laser output power variations were less than 1% (peak-to-peak). The laser has exhibited stable operation for 300 h without discharge deterioration. The above allows us to claim that the presented hollow-cathode discharge continuous wave He-Cd+ laser module should be useful as a simple, short, long-lived, multicolour laser source, operating at milliwatt output power levels. However, for higher output power level demands (tens of milliwatts) three or four laser modules must be used.