PURPOSE: To obtain an epoxy resin composition whose color tone changes from black to white when irradiated with laser beams by mixing an epoxy resin composition containing a curing agent with a specified composite metal oxide as a laser beam marking material.

CONSTITUTION: This composition is prepared by mixing an epoxy resin composition containing a curing agent with a composite metal oxide containing chromium, copper and manganese as a laser beam marking material. The amount of the composite metal oxide is 1.0-35wt.%, desirably 1.5-20wt.%, based on the total composition. When the amount of the compound oxide is out of this range, the composition can not give a sharp print. Examples of articles marked with laser beams include resin-coated electronic and electric components such as capacitors, resistors, diodes and ICs and sealing resin casings.