An actinic ray-sensitive or radiation-sensitive resin composition comprising: an alkali-soluble resin having a phenolic hydroxyl group; and a crosslinking agent having two or more hydroxymethyl groups or alkoxymethyl groups in total within the molecule, wherein the crosslinking agent includes a crosslinking agent, the crosslinking agent has a molecular weight of 420 or more and also has two to four hydroxymethyl groups or alkoxymethyl groups in total within the molecule, the content of the crosslinking agent is 60 mol% to 100 mol% based on the total amount of the crosslinking agent, and the total concentration of hydroxymethyl groups or alkoxymethyl groups in the crosslinking agent is 0.30 mmol/g or higher relative to 1 g of the solid content in the actinic ray-sensitive or radiation-sensitive resin composition, wherein the crosslinking agent is a compound represented by the following General Formula (I-b) or, wherein in General Formula (I-b), each R 1 independently represents a hydrogen atom, an alkyl group, an aryl group, a hydroxymethyl group, an alkoxymethyl group, or a group represented by -CH 2 -O-R 11, and R 11 represents an aryl group or an acyl group, provided that, in the whole molecule, two or more R 1 's are a hydroxymethyl group or an alkoxymethyl group, and Z b represents an atomic group necessary for forming a ring together with the carbon atom in General Formula (I-b), and this ring may have a substituent, and in General Formula, each of X 1 and X 2 independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a hydroxymethyl group, or an alkoxymethyl group, provided that at least one of two X 1 's is a hydroxymethyl group or an alkoxymethyl group, in the case where both of two X 1 's are a hydroxymethyl group or an alkoxymethyl group, Y 1 represents a carbon atom, a nitrogen atom, or an oxygen atom, and in the case where one X 1 is neither a hydroxymethyl group nor an alkoxymethyl group, Y 1 is a nitrogen atom and also X 2 is a hydroxymethyl group or an alkoxymethyl group, Y 2 represents a single bond, an alkylene group, or a cycloalkylene group, Z 2 represents an organic group, n is 2 when Y 1 is a carbon atom, n is 1 when Y 1 is a nitrogen atom, and n is 0 when Y 1 is an oxygen atom, and any two of X 1, X 2, and Y 2 may be bonded to each other to form a ring. an alkali-soluble resin having a phenolic hydroxyl group; and a crosslinking agent having two or more hydroxymethyl groups or alkoxymethyl groups in total within the molecule, wherein the crosslinking agent includes a crosslinking agent, the crosslinking agent has a molecular weight of 420 or more and also has two to four hydroxymethyl groups or alkoxymethyl groups in total within the molecule, the content of the crosslinking agent is 60 mol% to 100 mol% based on the total amount of the crosslinking agent, and the total concentration of hydroxymethyl groups or alkoxymethyl groups in the crosslinking agent is 0.30 mmol/g or higher relative to 1 g of the solid content in the actinic ray-sensitive or radiation-sensitive resin composition, each R 1 independently represents a hydrogen atom, an alkyl group, an aryl group, a hydroxymethyl group, an alkoxymethyl group, or a group represented by -CH 2 -O-R 11, and R 11 represents an aryl group or an acyl group, provided that, in the whole molecule, two or more R 1 's are a hydroxymethyl group or an alkoxymethyl group, and Z b represents an atomic group necessary for forming a ring together with the carbon atom in General Formula (I-b), and this ring may have a substituent, and each of X 1 and X 2 independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a hydroxymethyl group, or an alkoxymethyl group, provided that at least one of two X 1 's is a hydroxymethyl group or an alkoxymethyl group, in the case where both of two X 1 's are a hydroxymethyl group or an alkoxymethyl group, Y 1 represents a carbon atom, a nitrogen atom, or an oxygen atom, and in the case where one X 1 is neither a hydroxymethyl group nor an alkoxymethyl group, Y 1 is a nitrogen atom and also X 2 is a hydroxymethyl group or an alkoxymethyl group, Y 2 represents a single bond, an alkylene group, or a cycloalkylene group, Z 2 represents an organic group, n is 2 when Y 1 is a carbon atom, n is 1 when Y 1 is a nitrogen atom, and n is 0 when Y 1 is an oxygen atom, and any two of X 1, X 2, and Y 2 may be bonded to each other to form a ring.