Reactor

A reactor, comprising:

• a coil including a pair of winding portions arranged in parallel;
• a magnetic core to be arranged inside and outside the winding portions;
• a holding member for specifying mutual positions of the coil and the magnetic core;
• a case for accommodating an assembly including the coil, the magnetic core and the holding member;
• and
• a sealing resin portion to be filled into the case,
• wherein:
• the case includes a bottom plate portion, the assembly being placed on the bottom plate portion, a side wall portion in the form of a rectangular tube for surrounding the assembly, and an opening facing the bottom plate portion,
• the side wall portion includes a pair of long side parts facing each other and a pair of short side parts facing each other,
• the assembly is so accommodated into the case that an axial direction of each winding portion is along a depth direction of the case,
• the magnetic core includes an outer core portion to be arranged outside the winding portions and on the opening side,
• the holding member includes an outer wall portion for covering at least a part of an outer peripheral surface of the outer core portion and a protruding portion projecting from the outer wall portion toward one of the short side parts, and
• a clearance is provided between at least one of the long side parts and the protruding portion when the case is viewed from above.