According to a method of manufacturing a microwave tube collector of this invention, a copper plating layer in which powder particles of a material having a secondary electron emissivity of not more than 1 are dispersed and precipitated is formed on a surface of a collector electrode. Only the copper plating layer is selectively etched for a predetermined period of time to increase the degree of exposure and the surface area of the powder particles of the material having a secondary electron emissivity of 1 or more in the copper plating layer.