The present invention provides a honeycomb structure formed from a thermoplastic resin composition comprising: aromatic polyamide (A) which includes diamine units containing at least 70 mol % of xylylenediamine units and dicarboxylic acid units containing at least 50 mol % of C4-20 α,ω-linear aliphatic dicarboxylic acid units; and aliphatic polyamide (B) which includes aliphatic groups as repetitive units and in which the total of 10 to 24 carbons form the aliphatic groups. The composition ratio of aromatic polyamide (A):aliphatic polyamide (B) is within a range of 100:25 to 400 by mass standard. Also provided is a sandwich structure obtained by disposing flat plates at the top surface and bottom surface of the honeycomb structure, and a honeycomb substrate obtained by molding the thermoplastic resin composition into a film or a sheet.