Provided is a support member assembly suitable for use in a contact probe head comprising a support member formed with a plurality of holder holes for supporting conductive contact members in a mutually parallel relationship, and a reinforcing member integrally formed with the support member and extending in a part of the support member devoid of any holder holes. The reinforcing member increases the overall mechanical strength of the support member assembly, and prevents the thermal deformation of the support member. Because the holder holes are formed in the support member made of material suitable for forming holes, such as plastic material and ceramic material, the holder holes can be formed at high precision and at low cost.