PROBLEM TO BE SOLVED: To provide a crosslinking machine in which a thermoplastic resin can be crosslinked while preventing generation of a void or a concave, an apparatus for producing a thermoplastic resin foam, a method for crosslinking the thermoplastic resin, and a method for producing the thermoplastic resin foam.SOLUTION: The crosslinking machine includes: a pair of heat transfer plates 32, 42 between which a sheet 10a of a thermoplastic resin composition, which contains the thermoplastic resin and a crosslinking agent, is held and from which the held sheet is sent out to one direction; and heating bodies 36, 46 for heating the sheet 10b of the thermoplastic resin composition through the pair of heat transfer plates 32, 42. A plurality of through-holes for venting the gas generated from the thermoplastic resin composition are formed on at least one of the pair of heat transfer plates 32, 42. The heating body 36 or 46 has an abutting part 36a or 46a, which is disposed on the plate surface side of the hea
