This electronic component of the rotary switch type may include: a casing; a disk shaped rotor (34), rotatably supported in the casing, and formed with a cam pattern system; a contact system which is actuated by the cam pattern system (36) as the rotor is rotated; and a sheet spring (10). The sheet spring has: two pressure portions (12a, 12b); a substantially flat portion (F), intermediate between the two pressure portions, which is stressed so as to press the two pressure portions against the cam pattern system as the rotor is rotated, for providing detent action for the rotor; and a fixing portion, fixed to the casing, and proximate and connected to the substantially flat portion. There may be two each of the substantially flat portion and the fixing portion (48). As a specialization, this sheet spring may be generally ring shaped with a generally circular interior outline and a generally square exterior outline, and its two pressure portions may be two of its diagonally opposed corner portions which are creased so as to define projections opposing the cam pattern system, while its two substantially flat portions may be the other two of its diagonally opposed corner portions which are creased so as to press its two pressure portions against the cam pattern system. Also, this electronic component may include a resin casing with a terminal passing through it and a hole formed through it from its surface to the terminal, with some thermosetting bonding agent filled into the hole and sealing the terminal to the casing.