To provide a honeycomb panel material, which is extremely reduced in weight, has strong stiffness, has no problem of paper powder scattering like corrugated cardboard or the softening deformation caused by moisture absorption, is usable in the open air subjected to wind and rain or a clean room without hindrance and can be manufactured inexpensively, as a perfectly new panel material.

This honeycomb panel material is constituted by bonding a non-stretchable flat sheet 2 to an uneven molded sheet 1 made of a synthetic resin having a group of independent recessed parts 11 arranged densely to the surface thereof and having a group of independent protruded parts 12 inverted with respect to the independent recessed parts 11 on the rear thereof so as to integrate the same with a large number of the apexes 12a, etc. of the group of the independent protruded parts 12 on the rear of the uneven molded sheet 1.