The present invention provides a polyvalent alkyne compound which is excellent in heat resistance, a heat convertible resin composition, a heat curing and an insulating material. The polyvalent alkyne compound represented by the following formula 1 contains the aromatic hydrocarbon atoms with a high proportion, so that the heat curing which is excellent in heat resistance is obtained by carrying out the heating curing on the heat convertible resin composition containing the polyvalent alkyne compound. In the formula 1, Ar1 is an aromatic hydrocarbon which can have 1 to 3 hydrocarbon substituent groups having 1 to 6 carbons and of which the carbon number is 6 to 30; X1 is an alkyl which has the aromatic hydrocarbon atoms of which the carbon number is 6 to 18 and of which the carbon number is 6 to 30, n is an integer of 1 to 10, A is a structure or the hydrogen represented by the formula 2, and more than 50% of the A has the structure represented by the formula 2.