Adhesive agent and adhesion method

An adhesive agent comprising:

• a chloroprene copolymer latex containing a chloroprene copolymer (A);
• and
• a metal oxide (B), wherein
• the chloroprene copolymer (A) is a copolymer of a monomer group containing chloroprene (A-1), α,β-unsaturated carboxylic acid (A-2), and 2,3-dichloro-1,3-butadiene (A-3),
• when an amount of the chloroprene copolymer (A) is 100 parts by mass, the chloroprene copolymer (A) contains 80.0 parts by mass or more and 99.4 parts by mass or less of a unit derived from the chloroprene (A-1), 0.5 part by mass or more and 10.0 parts by mass or less of a unit derived from the α,β-unsaturated carboxylic acid (A-2), and 0.1 part by mass or more and 4.0 parts by mass or less of a unit derived from the 2,3-dichloro-1,3-butadiene (A-3),
• the chloroprene copolymer (A) has a tetrahydrofuran-soluble component soluble in tetrahydrofuran and a weight average molecular weight of the tetrahydrofuran-soluble component is 80000 or more and 90000 or less, and
• when an amount of the metal oxide (B) based on 100 parts by mass of the chloroprene copolymer (A) is defined as Y part(s) by mass and the weight average molecular weight of the tetrahydrofuran-soluble component is defined as X, a content of the metal oxide (B) satisfies Formula:
• −1.2×X/100000+1.6<Y<−4.2×X/100000+5.7.