A pipe connecting structure for a pipe-type modular wiper apparatus includes: a first bracket to which a wiper motor is fastened; and a second bracket to which a wiper shaft is fastened and which is, via a pipe member, integrally connected to the first bracket to which a wiper motor is fastened. The pipe member is integrally fastened to the brackets by integrally inserting a pipe nut into an insertion hole formed at a position at which the pipe member is connected to the bracket in such a manner that a bolt is, in a threaded manner, inserted from the bracket side in a state where the bracket is brought into contact with a head portion of the pipe nut projecting over the pipe member. A recess-groove shape fastening groove portion is formed in a portion of the first bracket to be tightened by the bolt, and the pipe fitting groove portion has a depth with which the pipe member can be fitted by a degree larger than the half of the pipe member. Two introduction surfaces of the pipe fitting groove portion through which the pipe member is introduced are made to be parallel surfaces facing a direction of a tangent of the outer circumference of the pipe member.