A link unit comprising: two spaced-apart first chain plates, each of said first chain plates having a first inner end section, a first outer end section that is offset from said first inner end section, an inner surface that faces the other one of said first plates, and an outer surface that is opposite to said inner surface, said first inner end section is formed with a through hole, said first outer end section is formed with a connecting hole that has a first hole portion, a second hole portion, and a neck portion located between said first and second hole portions(326,327); the one of said first chain plates has an abutment surface that is recessed from said outer surface of the one of said first chain plates and that extends around said second hole portion of the one of said first chain plates; two spaced-apart second chain plates and a connecting rod, each of said second chain plates having a second inner end section, and a second outer end section that is offset from said second inner end section, said first inner end sections of said first chain plates being disposed between said second outer end sections of said second chain plates, said connecting rod being inserted through said first inner end sections of said first chain plates and said second outer end sections of said second chain plates; an assembling rod inserted removably through said connecting hole of each of said first chain plates, and capable of being prevented from moving past said neck portion of each of said first chain plates so as to be positioned in said second hole portion of each of said first chain plates; wherein said assembling rod has a main rod body, two neck sections each of which is connected to a respective one of two opposite longitudinal ends of said main rod body and has a diameter smaller than that of said main rod body, and two end sections each of which is connected to an end of a respective one of said neck sections distal from said main rod body, each of said neck sections having a diameter greater than the width of said neck portion of said connecting hole, said one of end sections abutting against said abutment surface, said first hole portion of said connecting hole of each of said first chain plates having a diameter greater than that of said main rod body and that of one of said end sections of said assembling rod. two spaced-apart first chain plates, each of said first chain plates having a first inner end section, a first outer end section that is offset from said first inner end section, an inner surface that faces the other one of said first plates, and an outer surface that is opposite to said inner surface, said first inner end section is formed with a through hole, said first outer end section is formed with a connecting hole that has a first hole portion, a second hole portion, and a neck portion located between said first and second hole portions(326,327); the one of said first chain plates has an abutment surface that is recessed from said outer surface of the one of said first chain plates and that extends around said second hole portion of the one of said first chain plates; two spaced-apart second chain plates and a connecting rod, each of said second chain plates having a second inner end section, and a second outer end section that is offset from said second inner end section, said first inner end sections of said first chain plates being disposed between said second outer end sections of said second chain plates, said connecting rod being inserted through said first inner end sections of said first chain plates and said second outer end sections of said second chain plates; an assembling rod inserted removably through said connecting hole of each of said first chain plates, and capable of being prevented from moving past said neck portion of each of said first chain plates so as to be positioned in said second hole portion of each of said first chain plates; wherein said assembling rod has a main rod body, two neck sections each of which is connected to a respective one of two opposite longitudinal ends of said main rod body and has a diameter smaller than that of said main rod body, and two end sections each of which is connected to an end of a respective one of said neck sections distal from said main rod body, each of said neck sections having a diameter greater than the width of said neck portion of said connecting hole, said one of end sections abutting against said abutment surface, said first hole portion of said connecting hole of each of said first chain plates having a diameter greater than that of said main rod body and that of one of said end sections of said assembling rod.